Controlling Your Dopamine for Motivation, Focus & Satisfaction — Andrew Huberman

00:00- Welcome to the Huberman Lab Podcast,

00:01where we discuss science

00:03and science-based tools for everyday life.

00:05[upbeat music]

00:09I'm Andrew Huberman,

00:10and I'm a professor of neurobiology and ophthalmology

00:13at Stanford School of Medicine.

00:15This podcast is separate

00:16from my teaching and research roles at Stanford,

00:19it is, however, part of my desire and effort

00:21to bring zero-cost-to-consumer information

00:23about science and science-related tools

00:25to the general public.

00:26Before we begin today, just want to acknowledge

00:29that if you're watching this on YouTube,

00:30yes, I have a bandage on the left side of my face,

00:33I was trying to cook something for Costello and I

00:36and I got burned, burned myself, it was a cooking accident.

00:39I'm fine, no need to dwell on it, we can move on,

00:41but I just wanted to let you know

00:43everybody's going to be okay,

00:44he got a great meal, I got a burn and a great meal.

00:47Today's episode is brought to us by Four Sigmatic.

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05:49This month on the "Huberman Lab Podcast,"

05:51we're talking all about hormones,

05:52these incredible chemicals that can impact our mood,

05:56our behavior, our feelings of optimism or pessimism.

06:00The amazing thing about hormones

06:01is that hormones impact all those things,

06:04but all those things,

06:05how we feel and what we do and what we think

06:07also can impact our hormones,

06:09and so it's a really fascinating area of biology

06:12that impacts every single one of us every day

06:15both in wakefulness and in sleep

06:17and throughout the lifespan.

06:19Today, we're going to be talking about hormone optimization,

06:21and we're mainly going to be focusing

06:23on estrogen and testosterone and their derivatives.

06:27Last episode of the "Huberman Lab Podcast,"

06:29we talked about sexual development,

06:31that is, how the chromosomes, the gonads, and hormones

06:35impact what we call sexual development,

06:38leading all the way up to puberty.

06:39Today, we're mainly going to talk about processes

06:42that happen from puberty onward,

06:44although we might talk

06:45a little bit about development as well,

06:47so today, we're going to talk a lot about basic biology,

06:49but we're going to weave in a lot of practical tools

06:52along the way for how to optimize

06:54these incredibly powerful things that we call hormones.

06:57Before we dive into our discussion

06:59about hormone optimization,

07:00I want to raise what I think is a very important point

07:03that at least I hadn't heard of until recently,

07:06which is the concept of salutogenesis.

07:09Many of us are familiar with the concept of pathogenesis,

07:12the idea that there are all these scary diseases

07:14like dementia and heart disease and stroke,

07:18and all these things that await us

07:19if we don't take good care of ourselves

07:21and that might await us even if we do,

07:24that's the pathogenic model,

07:26salutogenesis is something I learned about

07:28from one of my Stanford Medicine colleagues,

07:30which is a different orientation

07:31toward health and well-being

07:32where you're taking on particular behaviors,

07:35you're taking on a particular stance

07:37towards nutrition and exercise, supplementation, et cetera,

07:40in order to promote well-being above where you would be

07:44if you were not doing those behaviors.

07:46Now, if you think about it, these two things,

07:48salutogenesis and the pathogenic model,

07:50are really two sides of the same coin,

07:53but I'll just give an example

07:54of how this might affect you in a real way.

07:57If you like exercise because it feels good, great,

08:01but many people exercise, or eat well, for that matter,

08:04in order to avoid heart disease or to avoid dementia,

08:08to avoid negative changes in body composition,

08:12and while that's powerful

08:14and certainly is the case that exercise

08:15will help you move away from all those things,

08:18the salutogenesis model differs

08:19in that it involves a mindset and an orientation

08:22towards doing those things in order to feels good,

08:25in order to enhance your level of energy,

08:27in order to improve endocrine function

08:29and metabolic function,

08:30so it's really part of the pathogenic model,

08:33and yet, salutogenesis is really more of a mindset

08:36toward why you would do these particular behaviors,

08:38and really, the most powerful mindset

08:40is going to be one where you are thinking

08:42about the pathogenic model,

08:43doing things so that you don't end up sick, et cetera,

08:46and to move away from sickness,

08:48as well as the salutogenic model where you're doing things

08:51in order to move towards health and well-being.

08:53We think of health and wellness nowadays,

08:55or the wellness community or wellness practices,

08:58and in many ways,

09:00that is the essence of the salutogenic model,

09:02but I found it very interesting

09:04to know that within the field of allopathic medicine,

09:06these two models exist

09:07but we don't hear about the salutogenic model

09:09quite as often,

09:11so it's just something to keep in mind,

09:12especially because of some of the mindset effects

09:14that were discussed in previous episodes,

09:16I'm not going to go into these in detail again right now,

09:19but if you might recall from the episode on food and mood,

09:23we talked about some of these incredible studies

09:25that were done by Alia Crum's group at Stanford and others

09:28showing that if you tell people

09:30that the behavior that they're about to do,

09:32in this case, it was people cleaning up hotel rooms

09:35because that was their job,

09:36if you tell them that it's good for them,

09:38then you see much greater positive health effects

09:41than if they aren't aware of that information

09:43that it's good for them,

09:44so we should really be thinking

09:45about not just moving away from disease and negative things,

09:49but also why certain things are good for us

09:51because it's well-established now

09:53from really good scientific studies

09:55that keeping in mind the positive effects of things

09:58can really have an outsized effect on well-being,

10:01right down to the level of our physiology.

10:05So let's talk about hormone optimization,

10:07today we're going to talk about hormone optimization

10:10in reference to estrogen and testosterone

10:13and their derivatives,

10:14now, estrogen and testosterone and their derivatives

10:17are what we call sex steroids,

10:20now, the sex steroids immediately call to mind sex,

10:24for obvious reasons,

10:25and steroids, meaning anabolic steroids,

10:28but I just want to emphasize that estrogen and testosterone

10:31are present in everybody,

10:33it's their ratios that determine their effects,

10:36and so today we're going to talk

10:37about how you can optimize their ratios

10:39depending on your particular life goals

10:41because the ratio of estrogen and testosterone

10:44in every individual has profound influence

10:48on feelings of well-being, feelings of optimism,

10:52feelings of anxiety or lack of anxiety, on reproduction,

10:56on sexual behavior independent of reproduction,

11:00they are profoundly powerful molecules,

11:03and we all make these molecules, to some degree or another,

11:06but there are also important behavioral tools,

11:09supplementation tools,

11:11as well as prescription drugs

11:13that can impact the ratios of testosterone and estrogen

11:16in really powerful ways,

11:18so we're going to cover all of that.

11:20I want to emphasize that when you hear

11:23sex steroids or steroid hormones,

11:25most people think about anabolic steroids,

11:28and of course, anabolic steroids

11:30are derivatives of testosterone or testosterone itself,

11:34and they are heavily used and abused in the sports community

11:38as well as outside the sports community,

11:40but there, of course, are many steroids

11:42that are not anabolic steroids

11:43that are also abused in sports.

11:45Today, we're not talking about drugs in sports,

11:47but I think that it carries such a heavy weight

11:49when people hear the word steroids,

11:51they think about anabolic steroids,

11:54so while today's discussion

11:55will certainly be relevant to physical performance,

11:57in fact, we're going to talk

11:58about how specific types of exercise,

12:00particular patterns of cold exposure,

12:02as well as particular patterns, believe it or not,

12:04of breathing can impact sex steroid hormones,

12:08both estrogen and testosterone,

12:11the discussion isn't really geared

12:12towards performance enhancement in sport,

12:14although we will do an entire episode,

12:16perhaps even an entire month

12:17related to performance enhancement in physical enterprises.

12:21So one of the first things to understand

12:23if you want to optimize your hormones

12:25is where they come from.

12:27There are a lot of different glands in the body

12:29that produce hormones,

12:30there's the pineal gland,

12:31some hormones are made in the hypothalamus,

12:34hormones are made by the gonads, the ovaries or the testes,

12:38you've got the thyroid gland,

12:40there are a bunch of different glands

12:41that make these different hormones,

12:43but when we're talking about the sex steroid hormones,

12:45estrogen and testosterone,

12:46the major sources are ovaries for estrogen

12:49and the testes for testosterone,

12:51although the adrenals can also make testosterone.

12:55Now, there are also some enzymes,

12:57enzymes are things that can change chemical composition,

13:01and the enzymes that we're going to talk about today

13:03are the aromatases mainly,

13:05the aromatases convert testosterone into estrogen,

13:09so in a male, for instance, that has very high testosterone,

13:13some of that is going to be

13:14converted into estrogen by aromatase,

13:16and aromatase is made by body fat,

13:18it's also made in the testes themselves,

13:21a lot of people don't realize this,

13:22but the testes actually have the capacity

13:24to manufacture estrogen and aromatase, albeit at low levels,

13:28but this turns out to be important

13:30for optimizing hormone levels in males at later points,

13:34and we'll discuss that.

13:36It's important to note that there's a huge range

13:38in terms of the levels of hormones,

13:40testosterone and estrogen, between individuals,

13:43and it actually occurs within individuals

13:46across the lifespan,

13:47I'm not going to throw out specific numbers

13:48of X picograms per deciliter, et cetera today

13:51because that's going to vary a lot,

13:53it's going to depend on whether or not you're measuring

13:54in picograms or nanograms and that sort of thing,

13:57if you want to examine your hormones,

13:58you should do that in conjunction with a medical doctor,

14:02ideally, an endocrinologist can help you

14:03sort out that information,

14:05but the important thing to know

14:07is that prepubescent females make very little estrogen,

14:10and when we talk about estrogen,

14:11we mainly talk about estradiol,

14:13which is the most active form of estrogen

14:15in both males and females.

14:17So prepubescent females, very low levels of estrogen,

14:20during puberty, levels of estrogen,

14:23AKA estradiol, basically skyrocket,

14:26and then across the lifespan, estrogen is going to vary

14:30depending on the stage of the menstrual cycle,

14:32but as one heads into menopause,

14:34which typically takes place nowadays

14:36somewhere between age 45 and 60,

14:38levels of estrogen are going to drop

14:40and then post-menopause levels of estrogen are very low.

14:44As well, testosterone will fluctuate across the lifespan,

14:46testosterone is going to be relatively low prepuberty in males,

14:51during puberty, it's going to skyrocket,

14:53and then the current numbers

14:55are that it drops off at about a rate of 1% per year,

14:59although we're going to talk about some data

15:01that show that there's actually tremendous variation

15:03in testosterone levels,

15:04there's actually a lot of examples

15:05of men in their 90s, their 90s,

15:09who still have testosterone levels

15:10that mimic pubertal levels,

15:12which is remarkable and speaks to the huge variation

15:14in testosterone levels across individuals.

15:17So let's talk about other sources of these hormones,

15:20and then it will make clear

15:22what avenues you might want to take

15:25in order to optimize these hormones.

15:27The other glands and tissues in the body

15:29that make these hormones, testosterone and estrogen,

15:32as I mentioned briefly, are the adrenals,

15:34so the adrenals right on top of the kidneys,

15:37and the release of these steroid hormones from the adrenals,

15:41in particular testosterone

15:42and some of its related derivatives,

15:45are mainly activated by competition,

15:48so let's talk about competition

15:50because it turns out that competition

15:53is a powerful influence on the sex steroid hormones,

15:58and the sex steroid hormones

15:59powerfully influence competition.

16:02So most people don't realize this,

16:03but most males of a given mammalian species

16:07never get to reproduce,

16:08in fact, they never even get to have sex at all,

16:11and we don't often think about that,

16:13but testosterone plays a powerful role

16:16in determining which members of a given species

16:19will get to reproduce,

16:20which ones of that species

16:22will actually get access to females,

16:25and so here I'm not talking about humans specifically,

16:28but it's well known in species like elephant seals,

16:33in species like antlered animals and rams, for instance,

16:38that the higher levels of testosterone

16:39correlate with access to females.

16:42Now, one interpretation of this is that the females

16:46are detecting which males have high testosterone

16:48and selecting them,

16:49they're more receptive to them,

16:50we're going to talk about receptivity for mating in a moment,

16:54but it's actually more so that the males

16:58that have higher testosterone forage further

17:02and will fight harder for the females,

17:05and this is really interesting

17:06because there's very good evidence now

17:08that testosterone can reduce anxiety,

17:11promote novelty-seeking,

17:13and promote competitive interactions,

17:17and so before you leap too far with this in your mind

17:19and think about all these human behaviors, just stay with me

17:21because there's a little bit of biology here

17:23that makes it all make sense

17:24and it turns out to be pretty simple.

17:28We have a brain region called the amygdala,

17:31in Latin, that just means almond,

17:32but the amygdala is most famous for its role in fear,

17:35we hear a lot about fear and the amygdala,

17:37but that the amygdala

17:38is really involved in threat detection,

17:40it sets our thresholds for anxiety

17:43and what we consider scary or too much,

17:47testosterone secreted from the gonads

17:49and elsewhere in the body binds to the amygdala

17:52and changes the threshold for stress,

17:55so I've said before on previous versions of this podcast

17:59and on other podcasts

18:00that testosterone has this incredible effect

18:03of making effort feel good,

18:05but what I was really referring to is the fact

18:07that testosterone lowers stress and anxiety,

18:10in particular, in males in a given species.

18:14Now, this is important

18:15because we often think of testosterone as creating,

18:19whatever, masculinization

18:20or it's, you know, virilization,

18:23or all these terms are thrown around,

18:25but what's it really doing

18:26when it comes to mate choice and competition?

18:28What it's doing is it's reducing the threshold for anxiety,

18:31and in doing so, it selects individuals

18:34of a given species to push further,

18:36being willing to suffer more,

18:40although it also reduces pain,

18:41so maybe they also suffer less,

18:42in pursuit of reproduction and females.

18:45Now, it's well known in humans that both males and females

18:49who have elevated levels of testosterone

18:51will engage in more novelty-seeking,

18:54and I do want to point out

18:55that even individuals without testes have testosterone,

18:59and peaks in testosterone have similar effects

19:02regardless of whether or not someone has ovaries or testes,

19:06testosterone increases generally lead to more foraging,

19:10more novelty-seeking, increases in libido,

19:13and increases in desire to mate,

19:16so it is the case that increases in testosterone

19:18promote competitive and foraging-type behaviors

19:22in humans and in nonhuman mammals,

19:26but it's also true that competition itself

19:30can increase androgens, such as testosterone,

19:32I want to repeat that, competitive environments themselves

19:36can increase testosterone.

19:38Now, some people have come to the conclusion

19:41that if you win, your testosterone goes up,

19:43and if you lose, your testosterone goes down,

19:46and to some extent, that's true,

19:48but that's not a direct effect on the gonads,

19:50that's actually mediated by the neuromodulator dopamine,

19:53we talked about dopamine

19:54in the episode on motivation and drive,

19:56and dopamine and testosterone

19:58have a remarkable interplay in the body,

20:01dopamine is actually released in the brain

20:03in ways that has the pituitary,

20:05this gland that sits over the roof of your mouth,

20:07release certain hormones

20:08that then go on to promote the release of more testosterone,

20:12and indeed, winning promotes more dopamine,

20:16and later, more testosterone,

20:18however, in the short term,

20:20just competing increases testosterone

20:23independent of whether or not you win or lose,

20:26so the short version of this

20:28is that competition increases testosterone,

20:32and this may be an ancient mechanism whereby the androgens,

20:36such as testosterone, are feeding back

20:38to encourage more competitive-type behaviors

20:41because every species,

20:42whether or not you're talking about reproduction

20:44or other resource allocation,

20:46is involved in competition,

20:47not every individual of a species

20:49gets access to the same number of mates

20:51or the same quality of mates,

20:53and this is true in both directions,

20:55for males and females and everything in between.

20:57So I just want to emphasize once more

20:59in case I went through it too quickly

21:01that increases in testosterone in females

21:04are also going to lead to increase in reproductive behavior

21:08or seeking out reproductive behavior, they increase libido,

21:11in fact, there's a particular phase of the menstrual cycle

21:13where testosterone peaks just before ovulation

21:17that, on average, leads female humans to seek out sex

21:22more than they would otherwise during their cycle,

21:24and this is all by self-report,

21:26but this is also while measuring

21:28things like testosterone-estrogen ratios, and so forth,

21:31so it's really interesting that a single molecule,

21:33regardless of chromosomal or gonadal background,

21:36is increasing seeking of mates across individuals,

21:41increasing desire to compete or willingness to compete,

21:44and lowering the threshold for stress and anxiety.

21:48It's important to point out

21:49that while increases in testosterone

21:51promote seeking of mates and reproduction

21:55in both males and females,

21:57in females, it's actually increases in estrogen

22:01that promote receptivity to mating,

22:03so testosterone is driving the seeking of sex

22:06and estrogen is promoting

22:09the actual act of sex from females,

22:11so-called receptivity, consensual receptivity.

22:14In males, it's interesting to point out that testosterone

22:17is promoting seeking of sex,

22:20but it's also estrogen in males that's important for libido,

22:24if estrogen levels are brought too low,

22:27then men will completely lose their libido,

22:29this is often not discussed or overlooked

22:32in the discussion about testosterone therapy

22:34and performance-enhancing drugs,

22:36people think that hyperandrogenized individuals,

22:39meaning people that have very high levels of androgen

22:41will have very high levels of libido, and they will,

22:44provided estrogen is available

22:46in sufficient ratios to match that testosterone,

22:49so it's not simply the case

22:51that high levels of testosterone

22:53produce a lot of sex and mating behavior

22:56and low levels of estrogen are good across the board,

22:58you actually need both in both males and females,

23:01it's just that in females, the testosterone levels

23:03are always going to be lower than the estrogen levels,

23:06and in males, the estrogen levels

23:08are always going to be lower than testosterone levels,

23:10so testosterone promotes sex-seeking behavior,

23:14and the real question then is,

23:16does sex itself promote testosterone?

23:18And the answer is somewhat complicated,

23:21but the short version is yes,

23:24and as you recall, sex has multiple stages,

23:28so there's the physical act of sex,

23:30there's the seeking of sex,

23:31and then there's orgasm and ejaculation.

23:34Now, it's important to distinguish between these

23:37because whether or not sex itself increases testosterone

23:41depends on whether or not the male ejaculates,

23:44and this is very important to understand

23:46because on a previous episode,

23:48I mentioned how dopamine increases with sexual activity,

23:51remember, dopamine and testosterone

23:53tend to increase linearly with one another,

23:56but then after ejaculation, there's a release of prolactin,

23:59and prolactin actually sets the refractory period in males

24:02during which he can't have sex again,

24:05and the duration of the refractory period

24:07will vary tremendously depending on how much and how long

24:10that prolactin release occurs.

24:12I also described in a previous episode

24:14how some people take vitamin B6,

24:17I'm not suggesting anyone do this,

24:17but take vitamin B6 in order to reduce prolactin levels

24:21and thereby reduce the duration of the refractory period,

24:24but getting at this question

24:26about testosterone and sexual behavior,

24:28it's important to distinguish

24:29between these different phases of reproduction

24:31or reproductive behaviors,

24:33so there are studies showing that sexual behavior itself

24:38can increase testosterone,

24:40there was a study published in 2011

24:41from Escasa et al., E-S-C-A-S-A,

24:45this is the stuff of textbooks, this is on PubMed,

24:48these are quality studies,

24:49showing that men who observe sex,

24:54so I guess this would be observing pornography,

24:56will have slight increases in testosterone

24:59during the observation,

25:01these people actually were willing to have blood draws taken

25:03while watching pornography,

25:05they had increases in testosterone that were very modest,

25:08of about 10%,

25:10whereas when people participated in sex,

25:13so they actually did this study where people had blood draws

25:15and they had real sex with their partners,

25:18and they had 70% increases in testosterone,

25:22so there are increases in testosterone

25:24that are quite significant

25:26during the physical act of sex

25:29and far less so during observing sex.

25:32Now, the question that I often get,

25:34in fact, it's one of the questions I get most often

25:36in the comments on YouTube,

25:37I don't know why that is,

25:38is whether or not ejaculation adjusts testosterone levels,

25:44and it turns out, there are two studies that I could find

25:47that were quality studies on PubMed that address this,

25:50that sex and ejaculation itself

25:52does not reduce testosterone levels

25:54although it will increase prolactin levels

25:57for the reasons I described a moment ago,

25:59however, abstinence or sex without ejaculation

26:05for a week or more

26:07will increase testosterone levels up to 400%,

26:11so the answer is actually complicated,

26:13it's not straightforward,

26:15what it means is that sex itself increases testosterone,

26:18however, abstinence also increases testosterone

26:21even further,

26:22so it's a nuanced answer,

26:24and I hope this is satisfactory, no pun intended,

26:27to those of you that have been asking me,

26:29what is the relationship between sex and ejaculation

26:33and testosterone and dopamine?

26:34It is nuanced, and you have to understand that nuance

26:38if you want to understand

26:39how certain behaviors impact hormones

26:41and how hormones impact those behaviors.

26:44As I mentioned before, in females,

26:46testosterone also primes the motivation to seek out sex,

26:51and sex itself also increases testosterone,

26:55but it also increases prolactin,

26:58so in both men and women,

27:00sex increases prolactin post-sex,

27:04it's just the way that the system works,

27:06it's that testosterone and dopamine increase

27:08in the seeking-out and the behavior of sex,

27:12and then after sex, prolactin levels go up,

27:15there's kind of a quiescence,

27:17the whole nervous system is promoted towards calm,

27:19and this may actually have something to do with pair-bonding

27:21and the encouragement of individuals

27:23to spend more time together

27:24to exchange different smells and hormones,

27:26and maybe even pheromones,

27:27and we're going to talk about pheromones in a moment.

27:29A few years ago, there was a lot of excitement

27:31about the hormone DHEA,

27:33which is mainly made by the adrenals,

27:36DHEA has been promoted as kind of a catch-all

27:40for increasing testosterone and estrogen

27:42in males and females,

27:43and indeed, DHEA will increase

27:46both testosterone and estrogen,

27:48this is something to be mindful of

27:49if you're thinking about taking DHEA

27:51or you're taking DHEA already.

27:54DHEA will increase both testosterone and estrogen,

27:57and the extent to which it increases one or the other

28:00will depend on whether or not you're starting off

28:02with more estrogen than testosterone

28:04or whether or not you're starting off

28:05with more testosterone than estrogen

28:07and whether or not you have a lot of aromatase,

28:09so for individuals that have a lot of aromatase

28:11being made by the testes or by body fat,

28:13if you take DHEA, there's a good chance

28:15that a fair portion of that

28:16is going to be shuttled towards estrogen production

28:19and not towards testosterone production,

28:21whereas in individuals that have

28:22low levels of testosterone to begin with,

28:24high levels of estrogen,

28:25there's a good chance that the DHEA

28:27is going to promote mainly estrogen production,

28:29at least that's what I could find

28:30from the research studies that I examined.

28:33So the way to think about DHEA,

28:34it's a kind of global promoter of the sex steroid hormones,

28:39and its specific effects are going to depend

28:41a little bit on where you started

28:43and whether or not you have ovaries or testes.

28:45So just as there are behaviors

28:46that can increase testosterone,

28:48there are behaviors that can decrease testosterone,

28:51and one of the most well-characterized ones in humans

28:55is becoming a parent.

28:58So expecting fathers have an almost 50% decrease

29:03in testosterone levels, both free and bound testosterone,

29:09as well, their cortisol levels, a stress hormone,

29:12drop by almost three-fold, which is incredible,

29:15and their estradiol levels double,

29:18so their estrogen levels double,

29:20so expecting fathers many people have known

29:23put on additional body weight,

29:24everyone always thought that it's because they're eating

29:26in parallel with their pregnant wife,

29:29but it turns out that these effects of reduced testosterone,

29:32increased estradiol, and reduced cortisol

29:35can all be explained by an increase in prolactin,

29:38so not just in humans, but in other species as well,

29:43when the male and female of that species

29:45are expecting young,

29:47they lay down more body fat,

29:49the assumption is that this is to prepare

29:51for long nights of no sleep,

29:53which occurs in many species, not just in humans,

29:56so it's really interesting that this hormone, prolactin,

29:59can start suppressing whole categories of hormones,

30:03sex steroid hormones,

30:04and can start increasing whole categories of other ones,

30:08so we hear about the dad bod,

30:09there are a lot of explanations for the dad bod

30:12that extend well beyond this podcast episode,

30:14but it is a well-known phenomenon

30:17that testosterone is going to drop,

30:18prolactin's going to increase,

30:20estradiol's going to increase in males and females

30:23that are expecting children.

30:25Now, how long that lasts is very interesting,

30:28it actually has to do with how much contact

30:31and how much contact with smells

30:34of the baby, of the offspring,

30:36the father happens to have,

30:37so how available or unavailable he is

30:39will actually impact his level of hormones,

30:41now, I'm definitely not promoting the idea

30:43that fathers or mothers take time away from their offspring

30:47in order to keep their testosterone levels high

30:48or to restore them,

30:50that's not what I'm saying at all,

30:51it's just interesting to point out

30:53that these evolutionary mechanisms push us toward

30:55or bias us toward particular categories of behaviors

30:59by influencing our hormones,

31:00which then feed back

31:02and promote more of that particular behavior

31:04because as I mentioned before,

31:05peaks in testosterone in males and females

31:08cause individuals to seek sex, not promote parenting,

31:12whereas reductions in testosterone,

31:14increases in prolactin, and decreases in cortisol

31:18move individuals of both sexes toward parenting behavior

31:21and less toward reproductive behavior.

31:23The other behavior that markedly reduces testosterone

31:27in both males and females

31:29and markedly reduces the desire

31:31for seeking sex and sex itself is illness,

31:35and many of you might say,

31:36"Well, duh, when people feel sick,

31:38"they don't feel like seeking out mates,

31:40"they don't feel like having sex,"

31:41but have you ever wondered why that actually is?

31:44Well, it turns out that it can be explained

31:46by the release of what are called inflammatory cytokines,

31:49so cytokines are related to the immune system,

31:52they travel in the lymph and in the blood,

31:54and they attack invader cells like bacteria and viruses,

31:57and under conditions of illness,

31:59we make a lot of different cytokines,

32:01some of them are anti-inflammatory,

32:03but some of them are pro-inflammatory,

32:05and the best-known example

32:07of a pro-inflammatory cytokine is IL-6,

32:10and it's known that IL-6, when injected into individuals,

32:15will decrease the desire for sex

32:17and eventually will reduce

32:19levels of testosterone and estrogen

32:21independent of feeling lousy,

32:23so the reason why people don't want sex when they're sick

32:27is because levels of IL-6 are increased.

32:30Now, this is important

32:31because as we start to think about the different ways

32:33to modulate the sex steroid hormones,

32:35so-called optimize the hormones,

32:38keeping levels of IL-6 low

32:40is going to be important for them to exert their effects,

32:44now, IL-6 doesn't just travel to the gonads

32:46and shut down the gonads,

32:47it actually has ways to interact with some of the receptors

32:51that the steroid hormones,

32:52estrogen and testosterone, bind to,

32:54and impact those receptors

32:55so that the sex steroid hormones can't have their effect.

32:58In short and put simply,

33:00inflammatory cytokines like IL-6

33:02are bad for sex steroid hormones,

33:04and so we're going to talk about how to modulate IL-6

33:07in the direction that you would want

33:09and how to increase another cytokine called IL-10,

33:13which is anti-inflammatory

33:15in ways that can help promote, or at least support,

33:17the sex steroid hormones.

33:19So as we move forward,

33:20we're going to now start to consider

33:22what sorts of behavioral practices,

33:24as well as other things,

33:26can modulate the sex steroid hormones

33:28in the directions that you want them to go,

33:31but before we do that,

33:32and in order to set the stage for that,

33:35you should be asking yourself,

33:37how is it, or why is it, at a mechanistic level,

33:41that behaviors can modulate hormones at all?

33:44If you think about it, it's kind of strange

33:46that just the mere act of being a parent or parenting

33:49can change testosterone levels so dramatically

33:52or estradiol levels so dramatically, what is it?

33:55Is it the sweat of the baby?

33:56Is it their saliva?

33:58Is it the sight of the baby?

33:59Is it holding the baby, or is it all those things?

34:02It turns out that many of those effects

34:05are because of smell,

34:06or in some cases, even possibly pheromones.

34:11Now, I talked about hormones,

34:12hormones, again, are a chemical, travels in the body,

34:14impacts tissues and cells elsewhere in the body,

34:17a pheromone is a chemical that's released

34:19by one member of a species

34:20that goes and impacts members elsewhere,

34:24but of the same species, or even of other species.

34:26Now, pheromone effects are absolutely well-established

34:30in lots of animal species,

34:32but they are very controversial in humans.

34:34Today, I'm going to talk

34:35about some of the well-established ones in animals,

34:38I've mentioned one or two of these before

34:40on previous podcasts,

34:41but I haven't mentioned several of them,

34:44and I'm going to talk about the evidence

34:47for pheromones in humans that are well-established.

34:51So the main ones in animals that are discussed

34:54are called the Lee-Boot effect, the Whitten effect,

34:56the Bruce effect, and the Vandenbergh effect,

34:58named after the people that discovered them.

35:01The Lee-Boot effect is when

35:02you house females of a given species together with no males,

35:07they start displaying longer, what are called estrus cycles,

35:10in many species, they don't have menstrual cycles,

35:12which are 28 days,

35:13they have estrus cycles which tend to be four days

35:16or some variant thereof.

35:20It's an interesting phenomenon because what it means

35:22is that the presence of the male itself

35:24is changing the ovulation cycle.

35:28Now, many people out there,

35:29I imagine mostly the people that are ovulating out there

35:33will say, "Of course, I notice I ovulate differently,

35:35"or my cycle changes when I'm in the presence of my partner

35:38"or I'm not,"

35:39but the pheromone effect

35:40that mirrors this Lee-Boot effect in humans

35:43has still not really been identified,

35:45nobody knows what the exact chemical is,

35:47but nonetheless, this is a strong effect in some animals.

35:50The other one is the Bruce effect,

35:52and this is a very dramatic effect

35:53whereby a pregnant animal will abort or reabsorb her fetus

35:59if the dad of those animals,

36:01the father that sired the litter,

36:03because these are animals, they're litters,

36:06is removed and a novel male is placed in her vicinity

36:11for about 48 hours,

36:12and what's interesting is the way that this happens

36:15is a pheromone that comes from male urine

36:19activates the gonadotropin-releasing hormone system

36:23and causes a reintroduction of the estrus cycle

36:28and a spontaneous abortion of the fetus.

36:30Now, a lot of people have taken the Bruce effect

36:33kind of to its extreme

36:34and asked whether or not in humans,

36:35miscarriages are caused by detecting the pheromones

36:38or odors of novel males, meaning the non-dad male,

36:42and that's still an open question,

36:43nobody knows if that's true or not,

36:45so I want to emphasize that.

36:47The other one is the Vandenbergh effect,

36:49and this is one I alluded to

36:50in a previous episode of the podcast,

36:51which is that puberty in females can be accelerated

36:55by placing a novel sexually competent male

36:58in with a young female who has not undergone puberty.

37:01There's also a version of this, which I haven't described,

37:04which is delay of puberty

37:06where you take juvenile female animals

37:09that have not undergone puberty

37:11and you put them with more mature females

37:13of the same species,

37:15and that introduction of more females will cause a delay,

37:20a significant delay in the onset of puberty.

37:23So these are all pheromone effects,

37:24and we know they're pheromone effects

37:26because they're not conscious,

37:28they also don't require actual contact

37:31with the other members of a given species,

37:33these are all effects that can be mediated

37:35by the urine from a given species

37:38or by the sweat of a given species,

37:40and speaking of sweat, the one pheromone effect

37:43that I'm very aware of from the published literature

37:47is a paper that was published in 1998

37:50by Stern and McClintock

37:52which was getting at this question

37:53of synchronization of menstrual cycles.

37:55Now, the whole idea of synchronization of menstrual cycles

37:59is pretty controversial,

38:01for a long time, people said,

38:02"Oh, this is absolutely a well-characterized phenomenon,"

38:06people in dormitories,

38:08their menstrual cycles would synchronize,

38:10people living in environments together,

38:11their menstrual cycles would synchronize,

38:14and then some studies came out

38:16that kind of undercut those data

38:18and said no, this actually doesn't happen,

38:20and it was kind of controversial,

38:21but there is a very clear effect

38:24that was described by Stern and McClintock,

38:26what they did actually was they took females,

38:30they charted their cycles,

38:32and then they had other females wear pads in their armpits

38:37and they collected sweat from those females,

38:40and then they took the sweat from those pads

38:43in those female's armpits,

38:45and they introduced them to women

38:46who had never had contact with the people who had sweated,

38:50they only had contact with their sweat,

38:52in fact, they swabbed it underneath their nose,

38:53and if that sounds gross, they dilute it in alcohol,

38:57so much so that they can't actually detect

38:59the odor of the sweat,

39:01that's actually very important because it's not the smell,

39:03it's the pheromone chemical itself,

39:06and it turns out the pheromone chemical itself

39:08can modulate the menstrual cycle,

39:12although it doesn't necessarily synchronize it

39:14with the sweater,

39:16what it does is it changes

39:18the duration and the pattern of ovulation

39:22relative to the so-called follicular phase,

39:24long and short of this

39:25is that the sweat and pheromones of females

39:30can modulate the menstrual cycle patterns

39:34of other adult females,

39:35it's just a question of whether or not they synchronize,

39:38and if you're kind of rolling your eyes now

39:39and saying, "Well, of course they do,

39:41"and this is really detailed,"

39:42this is how the science is done,

39:44and the reason why people are so skeptical

39:47about the presence of pheromone effects in humans

39:50is that there's no well-identified pheromone organ,

39:54you know, we have an area of our nose

39:55that's responsible for smelling, that's well-established,

39:58it's been observed in MRIs many, many times,

40:01in cadavers many, many times,

40:02in pretty much all individuals,

40:04but the vomeronasal organ,

40:07which is the pheromone-detecting organ,

40:08hasn't really been found in humans,

40:10there's something called Jacobson's organ,

40:12which is thought to be the organ in the nose,

40:14it's actually on the top of the roof of the mouth

40:17and in the kind of back of the nose,

40:18this is for you wine tasters,

40:20I never can pronounce this,

40:21what are they called, sommelier, whatevers,

40:24the people that are excellent at drinking

40:26and detecting the essences of wine

40:29that you have to go through all these tests

40:30in order to get certified as one of them,

40:32somebody tell me,

40:35they are using probably a similar mechanism

40:38of mixing taste and smell,

40:39and Jacobson's organ, if it exists,

40:42the vomeronasal equivalent in humans,

40:45is thought to be a combination of smell and taste.

40:49Now, it gets even weirder and cooler

40:52when you think about a given study that was done in humans

40:55where if you take hundreds of t-shirts from boyfriends,

41:00keep them separate,

41:01you take those t-shirts,

41:03you wash them many times separately,

41:05and then you offer them to the girlfriends,

41:08the long-time partners of those guys,

41:11and what you'll find is that the girlfriend

41:15can pick out her boyfriend's t-shirt

41:18among hundreds of other t-shirts,

41:21not because it smells different,

41:22but because something about it seems different,

41:25it might smell different to her

41:27in some way that's kind of imperceptible even to her,

41:30and the level of accuracy in detecting that t-shirt,

41:34her partner's t-shirt,

41:35is way above statistical significant thresholds,

41:39so much so that you almost have to say

41:41there's something about these effects

41:42that are real pheromone effects,

41:44although people still argue

41:46that there are no pheromone effects in humans,

41:47that it's all through olfaction,

41:49I think these are interesting and important to understand

41:50because it means that a lot of things

41:52coming through our nose,

41:53whether or not it's pheromones or smells,

41:55are impacting hormones and our ability to attach memories

41:59and kind of recognition of mates and other people,

42:02including our children, not just our mates,

42:04and of course, perfume manufacturers

42:06have really picked up on the idea of pheromones

42:08and have entire laboratories set up

42:10to build chemical compounds into perfumes

42:13that are designed to attract other mates,

42:15this is a well-established and well-documented phenomenon.

42:18And the last point I'll make about pheromones

42:21is that this combination of taste and smell

42:24is such a real thing in the animal world

42:27that there's something called the flehmen response,

42:30during the mating seasons for different animals,

42:33you can actually even see this in horses,

42:35but for animals that are seasonal maters,

42:37they'll do something called the flehmen response

42:38where they actually open their lips and their mouth

42:41and they expose their gums

42:43so that they can capture pheromones

42:46that are floating in the wind in the environment,

42:48they actually are looking for mates

42:50using their mouth and kind of sniffing around.

42:52If you own a dog

42:53and you watch the way that the dog will sniff around

42:55selecting where they want to urinate, males and females,

42:59they're bringing molecules into their nose,

43:02I know it sounds kind of gross, sniffing urine,

43:03but there are a lot of pheromones in urine of animals,

43:06a lot of pheromones that are traveling in the wind,

43:08again, whether or not this is happening in humans,

43:10I don't know, but then you think about the perfume thing,

43:12and here people are putting these scents on themselves

43:15that contain putative pheromones, human pheromones,

43:19and walking around hoping that their scents

43:21are going to evoke mate-seeking behavior

43:24from other individuals of the same human species,

43:26so we are among the animals in this behavior,

43:30independent of whether or not you believe

43:31pheromone effects exist.

43:32So let's get back to behaviors

43:34that can help optimize hormone levels.

43:37One of the main behaviors that's been shown

43:40to be associated with poor levels of estrogen

43:45relative to age-match controls for people with ovaries

43:49or lower levels of testosterone

43:51compared to age-match controls

43:53for people with testes, is apnea,

43:59apnea has everything to do with under-breathing

44:03and the buildup of too much carbon dioxide in the body,

44:06there are other effects of apnea as well,

44:08but if there's a consistent literature in this whole story

44:13about aging and reductions in hormones

44:15and general health and reductions in hormones, it's apnea.

44:20I went deep into the literature on advanced menopause,

44:23or when menopausal symptoms are exacerbated,

44:27and I went into the literature on andropause,

44:29or early-onset andropause,

44:31or levels of testosterone

44:33that are far lower than they should be for a given age,

44:36and in every case, you could find multiple papers

44:41that show that apnea, or poor efficiency of breathing

44:45and buildup of too much carbon dioxide in the body

44:48was a problem,

44:49mostly sleep apnea,

44:51although apnea in general was shown to be an issue

44:54negatively impacting hormones.

44:56Now, the directionality of this effect isn't entirely clear,

45:00it could be that reductions in estrogen cause apnea,

45:04and actually, there's some reason

45:05to believe that might be the case,

45:07I found at least one paper

45:09showing that there are estrogen receptors

45:11on some of the neurons that actually innervate the lungs

45:15and allow for the perception

45:17of how full or empty the lungs are,

45:19in other words, reductions in estrogen may adjust breathing

45:23by changing our sensitivity to our own lungs,

45:26now, that was true for males and females,

45:29remember, estrogen is both males and females,

45:31but as well, I found papers in which testosterone reductions

45:36were associated with apnea,

45:38and testosterone receptors are also found

45:41on a lot of cells in the so-called viscera,

45:44including the lungs,

45:46so again, the directionality of the effect isn't clear,

45:49but what's really interesting

45:50is that there are very clear ways

45:52in which patterns of breathing,

45:54especially patterns of breathing in sleep,

45:56can modulate hormones

45:58in ways that are immediately actionable

46:00and can serve to optimize both estrogen and testosterone

46:03regardless of whether or not you have ovaries or testes.

46:06So what is apnea?

46:08Apnea is under-breathing,

46:09or mainly, cessation of breathing during sleep,

46:13so people are holding their breath,

46:14and then they'll suddenly wake up,

46:16and actually I've talked about the physiological sigh

46:18on previous episodes of this podcast,

46:20of this pattern of double inhales followed by exhales

46:24that one can do consciously to reduce stress and anxiety

46:27and offload carbon dioxide,

46:28that pattern of breathing

46:29is actually what kicks in spontaneously

46:32anytime we have an apnea episode in sleep,

46:35although in many people who have apnea,

46:36they don't engage the physiological sigh.

46:39People who are dramatically overweight

46:42also suffer a lot from apnea during sleep,

46:45there's actually a lot of buildup

46:46of carbon dioxide in the body,

46:48and that can lead to excessive sleepiness during the day,

46:51inability to access the deeper phases of sleep,

46:54and it's well-established that going into deep sleep

46:59and getting the proper patterns

47:00of slow-wave sleep and REM sleep

47:01are important for hormone optimization.

47:04I talked about how to modulate sleep and optimize sleep

47:07in the first month of the "Huberman Lab Podcast,"

47:09so please check out those episodes if you have sleep issues

47:12or you want to work on your sleep,

47:13also check out Matt Walker's terrific book, "Why We Sleep,"

47:17and that will help you find various protocols

47:20to help you optimize your sleep,

47:22but the issue of breathing itself

47:25can be adjusted in the daytime waking hours

47:28in ways that can powerfully impact both sleep,

47:31reduce incidents of sleep apnea,

47:33and apparently from some emerging literature,

47:36can also help to optimize various hormones

47:39even just by breathing in particular ways while awake.

47:42So here's how this works,

47:44there's now a lot of literature

47:46showing that breathing through the nose,

47:47not through the mouth,

47:48is powerful for improving lots of things,

47:52first of all, it improves cosmetic features

47:54of the jaw and face,

47:55this was first well-established by my colleagues at Stanford

47:59in a book called "Jaws: The Story of a Hidden Epidemic,"

48:02this is by Sandra Kahn and Paul Ehrlich,

48:04who are both faculty at Stanford,

48:06has a forward by Robert Sapolsky, the great Robert Sapolsky,

48:10and it also has a heavy endorsement upfront

48:13by Jared Diamond, the author of "Guns, Germs, and Steel,"

48:16the Pulitzer winner,

48:17so a lot of heavy hitters on this book, "Jaws."

48:19It's not a book that a lot of people

48:21know about, unfortunately,

48:22but it really describes the benefits of nasal breathing

48:26and the terrible things that happen when people,

48:29in particular children, but adults also,

48:31are heavy mouth-breathers,

48:33so mouth-breathers have changes

48:35in the cosmetics of their face and jaw

48:37that are really bad in terms of attractiveness,

48:40and this was done in twin studies,

48:41you can look in the book and see some of this,

48:43it's really dramatic how being a mouth-breather

48:46tends to make the chin drop back behind the upper mandible,

48:49there's a lengthening in the face, a drooping of the eyes,

48:51it can be quite dramatic or modest

48:53depending on how much mouth-breathing.

48:55Now, sometimes we have to breathe with our mouths,

48:57but there's also a lot of data and studies

48:59described in this book, "Jaws,"

49:01that describe how nose-breathing in wakefulness and in sleep

49:06promotes all sorts of positive things

49:08related to not just cosmetics,

49:11but also the improvement of gas exchange

49:14of carbon dioxide and oxygen in the body,

49:17and as well, it can modify levels

49:20of different neurotransmitters and neuromodulators

49:22in ways that positively can impact hormones,

49:25so believe it or not, being a nasal-breather

49:28and avoiding being a mouth-breather

49:30can actually positively impact hormones,

49:33and in particular, the hormones testosterone and estrogen,

49:36although the way that it does that

49:38is by making you a better sleeper,

49:41which allows you to produce more testosterone

49:43and the appropriate amounts of testosterone and estrogen,

49:48but it does that in part through indirect mechanisms

49:52because deep sleep supports the gonads,

49:54the ovaries and the testicles

49:55and their turnover of cells and the production of cells,

49:58remember, in the ovary, particular cells

50:01and the egg follicles themselves make estrogen,

50:03and in the testicle,

50:07that the sertoli cells and the Leydig cells

50:10are important for the formation of sperm

50:12and for testosterone, respectively.

50:14So what does this all mean?

50:16This means we have to be breathing properly,

50:19it almost sounds kind of like, kind of new-agey,

50:22like, oh, you have to breathe properly

50:23to get your hormones right,

50:24but no, you have to breathe properly

50:26to get your breathing and sleep right

50:28so that your sleep can actually be deep enough

50:30and you're not entering apnea states,

50:32and then that will support gonad function,

50:35and I wouldn't be putting this out

50:36as one of the main behavioral tools upfront

50:39if it weren't for the fact

50:40that the effects of apnea on these hormones

50:42are dramatic and terrible,

50:44and the positive effects of getting breathing right

50:47on these hormones, testosterone and estrogen,

50:49are dramatic and wonderful,

50:50so let's talk about a few of those studies briefly

50:52so I can underscore the value of proper breathing

50:56in order to optimize hormones.

50:58So I was able to find at least four quality studies

51:01showing that when apnea is reduced in sleep, or eliminated,

51:06there are significant increases in testosterone in males

51:09and in proper estrogen to testosterone ratios in females,

51:13and the way that it works is very interesting,

51:17apparently, it works by reductions in cortisol,

51:21now, cortisol is a stress hormone

51:22that is released early in the day as we wake up

51:25and serves healthy roles in protecting us against infection,

51:27reducing inflammation, et cetera,

51:29but you don't want cortisol to be too high,

51:31and you certainly don't want it elevated too long

51:34throughout the day and night,

51:36and so we all know,

51:38because now we've been told a lot in the last decade or so,

51:41that getting proper sleep is important

51:43for all these aspects of health,

51:44getting proper sleep can really offset

51:46all the reductions in testosterone and estrogen

51:48and reductions in fertility that occur

51:50if we don't get enough sleep,

51:52but seldom is it discussed how sleep

51:54actually adjusts things like testosterone and estrogen,

51:57and it does it by modifying cortisol,

52:01so the molecule cholesterol

52:03can be converted into testosterone or estrogen,

52:06but there's a competition

52:09whereby the cholesterol will turn into cortisol

52:12and not testosterone,

52:13or it'll turn into cortisol and not estrogen

52:17if stress levels are too high,

52:19so the simple version of this

52:21is getting your breathing right during the waking hours,

52:24meaning primarily, unless you're working out really hard

52:27or there's some other reason why,

52:28you're maybe eating or speaking,

52:30that you need to be breathing through your mouth,

52:32you should be a nose-breather,

52:33there's really good evidence for that now,

52:36and in sleep, you also want to be a nose-breather

52:39because that's going to increase the amount of oxygen

52:41that you're bringing into your system

52:42and the amount of carbon dioxide that you're offloading,

52:45there are other positive effects of it as well,

52:47but you're basically reducing apnea,

52:49breath-holding in sleep leads to buildup of carbon dioxide

52:52and leads to increases in cortisol,

52:54which then decrease testosterone and decrease estrogen

52:58in negative ways across all sexes, okay?

53:01So the simple version of this is get your breathing right,

53:04so how do you do that, how do you get your breathing right?

53:05Well, for some people that have severe sleep apnea,

53:08they are going to need the CPAP machine,

53:10this is a machine that you actually put on your face

53:12and it helps you breathe properly in sleep.

53:14Many people, however, are starting to do this thing

53:16of taping their mouths shut,

53:17now, this sounds a little bit extreme,

53:20and you certainly don't want to do this

53:21in any way that's dangerous.

53:22James Nestor talked about this in his book,

53:25"Breath: The New Science of a Lost Art,"

53:27that simply taping shut the mouth,

53:29with some tape that will allow you

53:32to open your mouth if you really need to,

53:34during sleep can allow people to shift over

53:36from being mouth-breathers and snorers to nose-breathers.

53:40In the daytime, the best way to get good at nasal-breathing

53:44is to dilate the nasal passages,

53:46'cause a lot of people have a hard time

53:47breathing through their nose,

53:49and one way to do this

53:50is to just breathe through your nose more,

53:52and one way to do that is when you exercise,

53:54in particular, cardiovascular exercise,

53:56most of the time, provided you're not in maximum effort,

53:59you should be nasal-breathing.

54:01Now, for a lot of people,

54:02nasal-breathing during exercise is hard at first,

54:05but as you do it,

54:06because the sinuses have a capacity to dilate over time,

54:10you'll get better at it,

54:11the sinuses, if you haven't ever held a skull for,

54:15because of my job as a neuroscientist,

54:17I've held a lot of skulls,

54:18taken a lot of brains out of a lot of skulls,

54:21I teach neuroanatomy, and I've done that for,

54:23goodness, god knows how many species

54:25I've done that for, including human,

54:27but what the sinuses are is they're actually,

54:30what you've got are you got these little portals

54:32in the bone that run, you know, up here and down here,

54:35behind the nose and into the jaw,

54:37if you ever had a cold and your sinuses are stuffed up,

54:39you feel like you have congestion here and here

54:42and around your ears and in your cheeks and in your face,

54:44and that's because the sinuses

54:46are actually portals where the bones are fused together

54:50and interdigitated like this,

54:52but they're lined, of course, with mucus membranes,

54:55and as you start to nasal-breathe more,

54:57the nasal passages will start to dilate more,

54:59don't worry, you're not going to get giant nostrils,

55:01but what's going to end up happening

55:02is you're going to have an easier time

55:03breathing through your nose just from waking,

55:06so my advice would be

55:09breathe through your nose while exercising

55:11unless you're in maximum effort,

55:13pretty soon, what you'll find

55:14is you actually can create more output

55:17than you would if you were breathing through your mouth,

55:19and of course, there are exceptions to this,

55:21if you're swimming, follow that breath protocol,

55:23for fighters and martial artists,

55:24there's reason to do

55:26the kind of exhale breathing through the mouth,

55:28that shh kind of thing,

55:29you know, there are reasons to do that sort of thing

55:31for particular sports,

55:32but for most people who are

55:33kind of recreational athletes or exercisers,

55:36learn to be a nasal-breather,

55:37it has positive cosmetic effects,

55:39it reduces apnea, it offloads more carbon dioxide,

55:42it increases lung capacity, it dilates the sinuses,

55:45and it prevents apnea in sleep,

55:48so unless you have severe apnea and you need the CPAP,

55:51becoming a nasal-breather

55:53can have all sorts of positive effects

55:54by reducing cortisol, reducing apnea,

55:57and indirectly, raising testosterone and estrogen

56:01in the proper ratios,

56:02so this might seem kind of foundational and indirect,

56:05but when you go into the scientific literature,

56:07it comes through as one of the most powerful things

56:10that you can do that is zero cost,

56:13takes a little effort but it's zero cost,

56:15and it has all of these positive effects across the board,

56:19you know, both cosmetic

56:20and in sleep and hormonal, et cetera,

56:22so that's the first piece of behavioral advice.

56:25The second piece of behavioral advice

56:27relates to the viewing of light,

56:30and many of you have heard me talk about this before,

56:33and I'm not going to belabor the point

56:35that viewing bright light within the first hour of waking,

56:38whether or not it's from artificial light

56:39or ideally, from sunlight,

56:41has these powerful effects on sleep and wakefulness,

56:44but we have to return to this

56:45if you want to understand how light can impact hormones

56:49because hormones, light, and dopamine

56:52have a very close-knit relationship,

56:54so much so that your light-viewing behavior

56:57can actually have a direct effect

56:59on hormone levels and fertility,

57:01it can have a direct effect on hormone levels and libido,

57:05it can have a direct effect on hormone levels

57:08and your ability to heal quickly,

57:09and I'm not talking about shining light

57:11on particular injuries,

57:12that may or may not have positive effects,

57:15we can argue about that on a subsequent episode, it may,

57:18but what I'm talking about is viewing light with your eyes,

57:21so let's talk about that now

57:22because the scientific literature on this are robust

57:26and they extend back several decades,

57:28and yet, I think most people don't really understand

57:30how powerful this relationship is

57:32between light, dopamine, hormones,

57:35and all the great things that the sex steroid hormones do

57:37when they're available in your body in the proper ratios.

57:41In order to understand the powerful effects

57:42that light can have on the sex steroid hormones,

57:45we need to understand seasonal breeding animals,

57:49now, humans are not seasonal breeders,

57:51but if you understand the biology

57:52of how light impacts various neurotransmitters and hormones,

57:56you'll set yourself up for a deep understanding

57:58of what you should do with your light-viewing behavior.

58:01So several species of animals,

58:03many species of animals, in fact, like rabbits and fox,

58:08and various mustelids, like ferrets and ermines,

58:11change their pellage color across the seasons,

58:15this might be kind of a duh,

58:16but fox in winter are often white or light gray,

58:20and those same animals will be brown or darker-colored

58:25in the summertime and spring months.

58:27Now, those same animals breed in the spring,

58:29and they shut down breeding,

58:31they actually shut down ovulation,

58:33they often shut down testosterone production

58:36in the winter months,

58:37so right now I'm just correlating color of fur

58:41with tendency to breed,

58:43tendency to breed, as we know, is going to be related

58:46to the levels of sex steroid hormones,

58:47estrogen and testosterone.

58:50Now, why would these two things be linked?

58:53Well, it turns out that dopamine is the link between them,

58:57so dopamine has a precursor, that precursor is tyrosine,

59:02which is amino acid, comes from food,

59:04and when dopamine levels are high, as I mentioned before,

59:06there's a tendency for more gonadotropin-releasing hormone,

59:10luteinizing hormone, follicle-stimulating hormone,

59:12all the hormones that come

59:13from the hypothalamic-pituitary axis

59:15and stimulate estrogen and testosterone release

59:18from the ovary and testes,

59:22dopamine basically increases all of that.

59:25The precursor to dopamine is tyrosine,

59:28but the precursor to a lot

59:30of the melanin-producing elements of cells

59:33that give pigmentation, including for the hair,

59:37is tyrosine and tyrosinase, an enzyme,

59:41so yes, the same amino acid-based pathway,

59:45and many of the same enzymes that are devoted to dopamine

59:50and dopamine increasing the sex steroid hormones

59:53are devoted to giving pigmentation to the hair and skin,

59:58and this is why in the summer months, when days are longer,

1:00:02animals are breeding more,

1:00:05and this is also why in the winter months

1:00:07when days are shorter, animals are breeding less,

1:00:11this is also why in humans, many people, not all,

1:00:15feel an elevation in mood in the spring and summer months

1:00:18because of the amount of sunlight they're getting

1:00:21is increased relative to the winter months.

1:00:24Now, some of you may be saying,

1:00:25"I love the fall, I love the winter,"

1:00:27sensitivity to light in these dopamine systems

1:00:29has a strong genetic component,

1:00:32so you go to some areas of the world,

1:00:33I have relatives who are Scandinavian,

1:00:36and in some areas of Scandinavia,

1:00:38people know that there's

1:00:39a kind of seasonal affective disorder,

1:00:41there's kind of a seasonal depression

1:00:42and people get sadder and more quiescent in the winter,

1:00:45there's actually less going out,

1:00:47and therefore, there's less sexual behavior,

1:00:49there's less partying and things of that sort,

1:00:52but other people will say,

1:00:53"No, during the winter months, I feel great

1:00:56"and I love the holidays around winter," et cetera,

1:00:58so there's a lot of variation,

1:00:59but in general, the pathway is the following,

1:01:02increased viewing of sunlight, and it has to be to the eyes,

1:01:05it's not to the skin,

1:01:06increased viewing of sunlight

1:01:08increases dopamine levels in the brain,

1:01:11increased dopamine levels in animals and humans

1:01:13increases the amount of these melanocytes

1:01:17and the activity of these melanin-producing cells,

1:01:20which give pigmentation to the skin and hair,

1:01:23and indirectly, increase the amount

1:01:27of testosterone and estrogen,

1:01:29and thereby, reproductive behavior,

1:01:31feelings of well-being, social interactions,

1:01:34reductions in anxiety, et cetera,

1:01:36all of which should make sense

1:01:37based on what we've talked about already

1:01:39in terms of the biology

1:01:41and the impact of these steroid hormones

1:01:43on various aspects of the mind and body.

1:01:46So how does this translate to a protocol?

1:01:49This translates to the protocol of,

1:01:51if you want to optimize testosterone and estrogen,

1:01:54you need to get your light-viewing behavior correct,

1:01:57it's not just about optimizing your sleep,

1:02:00which is also important,

1:02:01it's about getting sufficient amount of light in your eyes

1:02:03so you have sufficient levels of dopamine,

1:02:06so the simple protocols for that I've reviewed before,

1:02:09but it means getting anywhere from 2 to 10 minutes

1:02:11of bright light exposure in your eyes early in the day,

1:02:14it is not sufficient to do this with sunglasses

1:02:16unless you have to do that for safety reasons,

1:02:18it's fine to wear prescription lenses and contacts,

1:02:21if you can't get sunlight for whatever reason,

1:02:23you want to use bright artificial light,

1:02:24but that is absolutely critical

1:02:26for timing the cortisol release properly,

1:02:29limiting cortisol release to the early part of the day,

1:02:31getting increases in dopamine that are going to promote

1:02:34the production of testosterone and estrogen

1:02:36to healthy levels,

1:02:38the other aspect of light-viewing behavior

1:02:39that's extremely important

1:02:42is to avoid bright light exposure to your eyes

1:02:45in the middle of the night,

1:02:46if you're viewing bright light in the middle of the night,

1:02:48you are suppressing dopamine release,

1:02:50if you're suppressing dopamine release,

1:02:52you are suppressing testosterone levels

1:02:55so much so that I would wager

1:02:57that a major effect of sleep deprivation

1:03:00on reducing testosterone and estrogen

1:03:04is not necessarily because of the lack of sleep per se,

1:03:06it's because usually when people

1:03:08are not getting enough sleep,

1:03:09they're getting too much light in their eyes

1:03:11in the middle of the night as well,

1:03:13a study on this has not been completed yet,

1:03:16but there are two studies published in "Cell" and "Neuron,"

1:03:19both Cell Press journals, excellent journals,

1:03:21showing that viewing bright light with the eyes

1:03:23in the middle of the circadian night

1:03:26has a detrimental effect on dopamine,

1:03:28and therefore has a detrimental effect

1:03:31on things like testosterone and estrogen,

1:03:33so you can't even begin to talk about supplements

1:03:36and other ways to optimize testosterone,

1:03:38diet and its effects on testosterone and estrogen

1:03:39and fertility and reproductive behavior, et cetera,

1:03:43until you get your breathing right,

1:03:44until you get things like your light-viewing behavior right,

1:03:48so bright light early in the day

1:03:49and throughout the day is great,

1:03:52view as much bright light, ideally sunlight, as you can,

1:03:55as much as you safely can,

1:03:56you obviously don't want to burn your retinas

1:03:58or damage your retinas,

1:03:59so never look at any light

1:04:00that's so bright it's painful to look at,

1:04:02but getting a lot of light in your eyes

1:04:04is not just about adjusting your sleep-wake rhythms,

1:04:06it's also about optimizing your sex steroid hormones,

1:04:09and avoiding bright light in the middle of the night

1:04:11is not just about not disrupting your sleep,

1:04:14it's also about optimizing the sex steroid hormones,

1:04:17and now that you understand

1:04:19a bit of how the sex steroid hormones work

1:04:20and how powerful they are for reducing anxiety

1:04:22and all these other effects,

1:04:24this should be straightforward to do,

1:04:26or hopefully it's inspired you

1:04:28to get your light-viewing behavior

1:04:29and your breathing behavior correct.

1:04:31In fact, in thinking about tools,

1:04:33for many people that are suffering

1:04:35from low levels of estrogen if they want higher levels

1:04:38or low levels of testosterone if they want higher levels,

1:04:41just getting the breathing and light-viewing behavior,

1:04:44which will indirectly support sleep behavior,

1:04:48can be a huge and positive effect

1:04:51on levels of sex steroid hormones.

1:04:53I can already anticipate that in hearing this,

1:04:56you might wonder whether or not viewing light

1:04:59is going to, for instance, increase your testosterone a lot

1:05:02when in fact you want your estrogen increased,

1:05:04or it's going to increase your estrogen a lot

1:05:06when you want your testosterone increased,

1:05:09everything I'm describing here is for people,

1:05:12regardless of chromosomal or gonadal background,

1:05:15so I'm trying to basically offer all this information

1:05:18in one swoop,

1:05:19but basically, if you're somebody who naturally has ovaries

1:05:24and has higher levels of estrogen than testosterone,

1:05:26then viewing bright light early in the day,

1:05:28because of dopamine's effects,

1:05:30is going to promote more estrogen

1:05:34and subtle increases in testosterone,

1:05:36whereas if you're somebody who starts off

1:05:37with more testosterone and lower estrogen,

1:05:40so somebody presumably who has testes

1:05:42or maybe you're supplementing with testosterone

1:05:44through other sources for whatever reason,

1:05:46bright-light viewing

1:05:47is going to increase testosterone and estrogen in parallel,

1:05:51but you're still going to maintain

1:05:52the ratio of testosterone to estrogen,

1:05:54in short, you don't have to worry

1:05:56that you're going to increase the wrong hormone,

1:05:57this is all about optimizing the ratios of hormones

1:06:00that you already have.

1:06:01Okay, so we've talked about breathing,

1:06:03we've talked about light,

1:06:04let's talk about a third element

1:06:07that there seems to be some excitement about lately

1:06:10for other reasons

1:06:11but that can actually have

1:06:12some pretty profound influences on hormone levels,

1:06:17and that's heat and cold,

1:06:19so as always, rather than just offer a tool,

1:06:21I'm going to tell you the underlying science

1:06:24as it relates to naturally occurring phenomena

1:06:26because, in understanding that

1:06:27and understanding the mechanism,

1:06:29you're going to be in a far better position

1:06:31to understand the tools and mechanisms

1:06:33and how you might want to adjust them for your own life.

1:06:36So now you understand the relationship

1:06:39between light, day length, dopamine, and hormone levels,

1:06:43and everyone should realize

1:06:45that temperature and day length are linked,

1:06:48and I'm sure as I say that,

1:06:49you're probably thinking, "Oh, of course."

1:06:51In summer, when there's more sunlight,

1:06:53days are longer, nights are shorter,

1:06:55in general, it tends to be warmer out,

1:06:57and in winter, when nights are longer, days are shorter,

1:06:59it tends to be colder out,

1:07:01and in the winter months,

1:07:03testosterone and estrogen tend to be lower

1:07:06in many animals and in humans,

1:07:10and in the summer months,

1:07:11because of the role of dopamine

1:07:13in promoting the sex steroid hormones,

1:07:16when days are longer and it's warmer,

1:07:18humans tend to make more estrogen and testosterone

1:07:21relative to the other months of the year.

1:07:24Now, these effects can be somewhat weak and modulated

1:07:27as opposed to in seasonally breeding animals

1:07:29where they're really dramatic, okay?

1:07:32But the point is that temperature

1:07:36and day length and sunlight,

1:07:38those are all intimately related

1:07:40because of the systems that we evolved in, right?

1:07:42So before we had artificial light

1:07:44and artificial heating and artificial cooling,

1:07:46our biology evolved under systems

1:07:48where temperature, day length, and the hormones

1:07:52were correlated with one another,

1:07:54so nowadays, there's a lot of interest in using cold

1:07:57as a way to stimulate testosterone,

1:07:59this is mainly because in the sports community,

1:08:03in particular, in the bodybuilding community,

1:08:05they are always seeking ways

1:08:07to maximize testosterone, dihydrotestosterone,

1:08:09keep estrogen to its minimum required

1:08:12to still have a libido and still have skin elasticity

1:08:15but also walk around with Saran-wrap skin,

1:08:17then all this kind of extreme stuff that happens there

1:08:20has led to a recent movement where, believe it or not,

1:08:23I heard this and I couldn't believe it, I went and checked,

1:08:25but although I didn't buy them,

1:08:26that on Amazon, you can actually find,

1:08:30they're literally underwear that have ice packs,

1:08:34so I think they are ice pack underwear,

1:08:35so that people are making themselves cold

1:08:38at the level of the gonads

1:08:39in order to try and increase testosterone and libido,

1:08:42sounds pretty crazy,

1:08:43but believe it or not,

1:08:46that and things like ice baths and cold showers

1:08:48can have positive effects on the sex steroid hormones,

1:08:53both testosterone, mainly in males,

1:08:55and estrogen, mainly in females,

1:08:57and you might say, "Wait, I thought cold

1:09:01"makes the reproductive axis kind of shut down a bit

1:09:04"or reduces testosterone and estrogen,"

1:09:07but it turns out it's not actually the cold

1:09:09that's having these effects in people,

1:09:11things like the ice bath, cold showers, cold-water swims,

1:09:15these ice underwear or whatever they are,

1:09:17can't believe that these actually exist, but they do exist,

1:09:21what happens is there's a rebound in vasodilation

1:09:25after cooling, so cooling causes vasoconstriction,

1:09:29and then after the cooling, there's a rebound vasodilation

1:09:33and there's more infusion of blood into the gonads.

1:09:36There's also an effect that's neural,

1:09:39so let me explain how this works

1:09:41because there are only a few studies on this,

1:09:43none of which looking at the frozen underwear,

1:09:45but that have looked at cold exposure

1:09:46and levels of androgens and estrogens,

1:09:49and it's kind of interesting,

1:09:50so you have to remember that the gonad,

1:09:53the ovaries and the testes are heavily vascularized.

1:09:57Remember, even at the level of the brain,

1:09:59GnRH, gonadotropin-releasing hormone,

1:10:01comes from neurons that, believe it or not,

1:10:03start off in your nose early in development,

1:10:06migrate into the hypothalamus.

1:10:07I'm not making that up, they started off in your nose

1:10:09and migrated to the hypothalamus.

1:10:10Those neurons extend processes, we call them axons,

1:10:14into the pituitary and release GnRH into the pituitary.

1:10:19There's a lot of vascularization within the pituitary,

1:10:22so now those hormones, or GnRH,

1:10:25can stimulate follicle-stimulating hormone,

1:10:27luteinizing hormone,

1:10:28which then are released and travel into the bloodstream.

1:10:32Then those hormones reach the ovary or testes,

1:10:36and they have to get into the ovary and testes,

1:10:39and the way they do that is through the vascular system,

1:10:43and people forget, but the vascular system

1:10:45and how constricted or dilated vessels are

1:10:49is controlled by neurons, all right?

1:10:53We discussed this during the discussion about stress

1:10:55in the stress episode,

1:10:57but it's well-known to neuroscientists

1:11:00that the best way to shut down neurons is to cool them,

1:11:04so there are a lot of examples of this

1:11:06in the scientific literature,

1:11:07but most people aren't aware of it

1:11:08because you're not digging around

1:11:09in the method section of these papers,

1:11:11but when we want to shut down neurons,

1:11:14we can do things like inject drugs that will do that,

1:11:16like lidocaine, you know, the stuff that makes you numb

1:11:18at the dentist,

1:11:19or you can use different inhibitors,

1:11:20but one of the best ways to do it experimentally

1:11:23is to just cool neurons,

1:11:24when you make neurons cold,

1:11:26because there's a temperature dependence

1:11:28of when neurons can be active and when they can't,

1:11:30the neurons shut down,

1:11:32so the most plausible explanation for why cold exposure,

1:11:36either through 1 to 10-minute ice bath or cold shower

1:11:40or the ice underpants thing,

1:11:41would increase testosterone or increase estrogen

1:11:45is that you're cooling the neurons

1:11:47that control vasoconstriction and vasodilation

1:11:50and shutting down the entry of blood,

1:11:55or at least reducing it,

1:11:56and hormones into the gonad,

1:11:58and then when the gonad and the surrounding area

1:12:02heats up again,

1:12:03you're getting a rebound hyper-vasodilation

1:12:06that delivers excessive levels of, not excessive,

1:12:09but increased levels of GnRH and other hormones

1:12:13and carriers and carrier proteins and so forth

1:12:16that would then stimulate the gonad

1:12:18to release more testosterone

1:12:20or would stimulate the gonad to release more estrogen,

1:12:22that's the most plausible explanation I can come up with,

1:12:25there aren't a lot of studies

1:12:26looking at direct effects of temperature on the gonad,

1:12:29and it's going to be a difficult study to carry out

1:12:32in any case because unless it were done in vitro in a dish,

1:12:35it's very hard to eliminate all the other things

1:12:38like vasoconstriction and vasodilation,

1:12:40put simply, we don't know whether or not cold and heat

1:12:42directly affect the production of testosterone and estrogen,

1:12:47we only know that cold and heat can modulate those,

1:12:51probably through indirect mechanisms

1:12:53like controlling the amount of blood flow

1:12:55by way of shutting down or activating the neurons.

1:12:57Now, there's a lot of lore

1:12:59around heating up the gonads too much,

1:13:01there's actually a whole set

1:13:04of pseudoscience webpages out there saying,

1:13:08"Well, if you want a girl,

1:13:09"you should conceive the child at this room temperature,

1:13:12"and if you want a boy,

1:13:13"you should conceive the child at this room temperature."

1:13:15I don't think there's really

1:13:16any firm scientific evidence for that, for either one,

1:13:20but there's some interesting literature

1:13:23about temperature dependence of production of hormones,

1:13:26and I think that it probably relates

1:13:27to these mechanisms of vasodilation

1:13:29and neural control over vasodilation,

1:13:32and of course, excessively high heat

1:13:34is not good for the testes,

1:13:36for sperm production, or for sperm health,

1:13:39sperm have all sorts of proteins in the cap,

1:13:41things like pentraxins and other things

1:13:43that cause them to swim faster

1:13:44when they're expressed properly and in the right locations,

1:13:47and heat actually alters the location and the function

1:13:50of a lot of those proteins, they're very heat sensitive,

1:13:52and so that's why excessive heat

1:13:54is truly not good for fertility,

1:13:56which may be independent of heat's roles

1:13:59in promoting estrogen or testosterone.

1:14:02Okay, so now we've talked about breathing,

1:14:04light, and temperature,

1:14:06we talked about parenthood, we talked about competition,

1:14:09and we talked about some pheromone effects,

1:14:11now let's talk about particular forms of exercise

1:14:15and how they modulate the steroid hormones,

1:14:18and then we're going to talk about various supplements,

1:14:22both in reference to testosterone

1:14:24and in reference to estrogen.

1:14:26So now let's talk about how exercise in its various forms,

1:14:29weight training, endurance work,

1:14:31weight training to failure, or less intense weight training

1:14:34can impact testosterone levels,

1:14:36but I want to remind you that we're talking about testosterone

1:14:39both in males and females,

1:14:41and based on what you know from earlier in the episode,

1:14:44testosterone can have numerous positive effects

1:14:46in both males and females provided they're in optimal range.

1:14:50So if you look on the web,

1:14:52people will say, "Oh, you know,

1:14:55"testosterone is increased by weight training,

1:14:57"you want to do these big, heavy compound movements,"

1:14:59squats and deadlifts and chins and things of that sort,

1:15:01but what about the scientific studies?

1:15:02Like, what's the actual basis for this?

1:15:03Because if you just take a step back

1:15:05and look at this from the perspective of a scientist,

1:15:07you'd say, okay, what is a squat?

1:15:09A squat is loading up a bunch of weights on a bar

1:15:12and then, you know, sitting down, essentially,

1:15:14and standing up over and over again.

1:15:17What's a deadlift?

1:15:17It's lifting heavy weights from the ground.

1:15:19Why would that increase testosterone, right?

1:15:22This is what's often not discussed in the weight training

1:15:24or even the exercise science community,

1:15:26what would actually stimulate the release of testosterone

1:15:30from the adrenals and/or testes,

1:15:31and which one is it, adrenals or testes or both?

1:15:34And that's often not discussed,

1:15:36but as a neuroscientist,

1:15:37these are the kinds of things we think about

1:15:38because we think always that genes don't create behavior,

1:15:43immune systems don't know when to be activated,

1:15:45lungs don't know when to inhale or exhale,

1:15:48hearts don't know when to beat

1:15:49except for the information that it gets from neurons,

1:15:52the nervous system controls all of that,

1:15:54and so really the answer has to be in the neural system

1:15:59that's related to these particular types

1:16:02of weight-bearing exercises.

1:16:04So when you go into this literature,

1:16:07it's kind of hard to find real mechanism,

1:16:09you see a lot of effects,

1:16:10you'll hear things like, androgen receptor content,

1:16:13meaning testosterone and its derivatives,

1:16:15receptor content following heavy-resistance exercise,

1:16:18and you'll find some examples

1:16:19that, for instance, you know, they do muscle biopsies,

1:16:23they can actually see receptor increases,

1:16:26looking at either high-volume

1:16:28or low-volume really intense exercise,

1:16:30and you can find a lot of that but not a lot of mechanism

1:16:33about how the nervous system would do this,

1:16:36and the reason you'd want to know how it can do it

1:16:38is that you could potentially build better protocols

1:16:41or figure out exactly what about these movements

1:16:45is triggering increases

1:16:46in androgen receptors and testosterone.

1:16:50So what's interesting is when you start digging

1:16:52into the more mechanistic studies,

1:16:55what you find is that heavy weight training,

1:16:58so this is weight training where the sets

1:17:01are done with anywhere from kind of one to eight rep range,

1:17:05and this translates differently

1:17:07depending on ratio of muscle fiber type and so forth,

1:17:10but where basically people are

1:17:11working at anywhere from like, 70% to 95% of their maximum,

1:17:15or sometimes even going

1:17:16right down to their one-repetition maximum,

1:17:18really kind of max effort,

1:17:21what you find is that using the nervous system

1:17:25in a way in which they're moving heavy loads,

1:17:27so that I would translate to recruitment

1:17:30of high-threshold motor units,

1:17:31for you muscle physiologists,

1:17:33and there's a rule in muscle physiology

1:17:36about the neuron recruitment for moving muscles

1:17:39where you basically use

1:17:40the minimum number of motor units of neurons

1:17:42to activate muscle as you possibly can,

1:17:45as loads increase, you have to recruit

1:17:46more and more neurons,

1:17:48you always hear about recruiting muscle fibers,

1:17:50but really, it's recruiting more neurons

1:17:52to recruit more muscle fibers,

1:17:55and what you find is that heavy weight training,

1:17:58but not weight training to failure

1:18:00where completion of a repetition is impossible,

1:18:03leads to the greatest increases in testosterone.

1:18:06Now, I'm sure there are a bunch

1:18:07of exercise jockeys out there

1:18:09that are going to come at me with a bunch of things

1:18:10where, oh, yeah, but high volume and this,

1:18:13and training to failure and that, sure,

1:18:16if you're willing to kind of put things side by side,

1:18:19adjust for exogenous testosterone treatment

1:18:22and all the rest,

1:18:23which was done in these studies,

1:18:25what you find in general

1:18:27is that weight training with heavy loads,

1:18:30so anywhere from one-rep maximum

1:18:32to somewhere in the six to eight repetition range,

1:18:35in males or females,

1:18:37increases testosterone significantly,

1:18:39and it does it for about a day, sometimes up to 48 hours,

1:18:43and the studies that I found

1:18:45which seem to hold the most rigor or weight

1:18:48based on where they're published

1:18:49as opposed to being published

1:18:50in the journal of "Never Heard of It,"

1:18:51they're published in good-quality

1:18:53exercise physiology journals,

1:18:57for instance, the paper by Ratamess,

1:18:59R-A-T-A-M-E-S-S et al.,

1:19:04which was published in 2005,

1:19:06which talks about modulations in androgen receptor content

1:19:09after heavy resistance exercise,

1:19:10looks at going to failure and not to failure,

1:19:13the work of Izquierdo et al. published in 2006,

1:19:18"Differential Effects of Strength Training

1:19:20"Leading to Failure Versus Not Failure

1:19:21"on Hormonal Responses, Strength, and Power Gains,"

1:19:24you know, there are a lot of studies here

1:19:26and I will certainly put the links to these in the caption,

1:19:29many of these actually include Duncan French,

1:19:31who runs the UFC training center

1:19:34who I've had the privilege of meeting

1:19:35and discussing some of this with before,

1:19:38as well as other authors, of course,

1:19:39but they all point to the fact

1:19:41that there's something about the engagement of the neurons

1:19:44that recruit high-threshold motor units in muscle

1:19:48when moving heavy loads, but not to failure,

1:19:51that has to provide some sort of feedback signal,

1:19:54either to the gonad to produce more testosterone,

1:19:56or is increasing the activity of receptors in the body.

1:20:01Now, why do I say that?

1:20:03Well, this is the puzzle, right?

1:20:05How is it that a particular movement,

1:20:06just like how is it that interacting with your child,

1:20:09is increasing or decreasing testosterone?

1:20:11This is the kind of fundamental question

1:20:13at the mechanistic level,

1:20:14and we answered the question for child-rearing,

1:20:17it has probably something to do with smell and pheromones,

1:20:19although I'm sure there are other cues as well,

1:20:21but there's clearly a influence

1:20:26of hard work at the neural level

1:20:29and then at the muscular level for increasing testosterone,

1:20:33and there's also clearly an effect of working too hard

1:20:37and presumably increasing cortisol too much,

1:20:40although I'm speculating there,

1:20:41in terms of reducing testosterone,

1:20:44and so the reason we're getting nitty-gritty about this

1:20:46is because ultimately, we'd really like to understand,

1:20:48what are the optimal protocols?

1:20:50You know, out there in the literature,

1:20:51you hear, move heavy objects to increase testosterone,

1:20:54some of that will be converted

1:20:55to the more powerful androgen, DHT,

1:20:57by 5-alpha reductase et cetera,

1:20:59but we really don't understand yet

1:21:02how these particular behaviors increase testosterone

1:21:04and whether or not it's doing that

1:21:06by modulating the receptors

1:21:07or it's modulating testosterone release directly,

1:21:09presumably, testosterone release directly

1:21:11and sensitivity of the receptors,

1:21:13that what most of the muscle physiology studies

1:21:15that I was able to find point to,

1:21:17but this basically boils down

1:21:18to a particular set of protocols

1:21:20where if you want to increase testosterone,

1:21:22for whatever reason,

1:21:24that weight training with heavy loads but not to failure

1:21:27seems to be the best-supported,

1:21:30at least scientifically supported, solution to that,

1:21:33now, it may not raise your testosterone levels

1:21:35as high as you want,

1:21:36but it's definitely taking things in the correct direction.

1:21:39Now, many of you might be endurance athletes

1:21:42or also enjoy exercise

1:21:44besides heavy-weight-bearing exercise,

1:21:46and there are several studies

1:21:48exploring whether or not endurance activity

1:21:52can increase or decrease androgen levels

1:21:55and whether or not you combine

1:21:57endurance activity and weight training,

1:21:59whether or not that has any effect

1:22:00if you do the endurance activity first or second,

1:22:03and the takeaway from all of this

1:22:06was that endurance activity, if performed first,

1:22:09leads to decreases in testosterone

1:22:12during the weight training session

1:22:14as compared to the same weight training session done first

1:22:17followed by endurance activity,

1:22:18in other words, if you want to optimize testosterone levels,

1:22:21it seems to be the case that weight training first

1:22:23and doing cardio-type endurance activity afterward

1:22:27is the right order of business.

1:22:29Now, when these are done on separate days,

1:22:31it doesn't seem to have an effect,

1:22:32they showed no statistical interaction,

1:22:35but it seems that if you're going to do these

1:22:37in the same workout episode

1:22:39that it's move heavy loads first,

1:22:41then do cardiovascular exercise,

1:22:43so there's a little bit of data

1:22:45looking specifically at how endurance exercise

1:22:47impacts testosterone and its derivatives,

1:22:50and it's very clear that high-intensity interval training,

1:22:53sprinting et cetera,

1:22:54which somewhat mimics the neural activity

1:22:57that occurs while moving heavy weight loads,

1:23:00is going to increase testosterone

1:23:01and there's ample evidence for that in the literature,

1:23:04and that endurance exercise that extends beyond 75 minutes

1:23:09is going to start to lead to reductions in testosterone,

1:23:12presumably by increases in cortisol,

1:23:14but of course, the intensity of the exercise

1:23:17is going to be important too,

1:23:19you know, I don't think anyone really believes

1:23:21that hiking for three hours

1:23:23is going to reduce your testosterone,

1:23:25whereas I think if one were to go out

1:23:27and run hard for three hours

1:23:29that you can imagine there'd be reductions in testosterone

1:23:31by way of increases in cortisol,

1:23:34and so while this area certainly needs more research,

1:23:37it's pretty clear that limiting the endurance exercise

1:23:40to 75 minutes or less, not making it too intense,

1:23:43is one way to keep cortisol from going through the roof,

1:23:46but I've talked on previous episodes,

1:23:48and there are a lot of others who have talked out there

1:23:50about how to clamp cortisol,

1:23:51how to keep cortisol more reduced,

1:23:53this is also one of the reasons why, you can imagine,

1:23:56that various individuals,

1:23:57either for competition or just for their own purposes,

1:24:00rely on testosterone therapy, exogenous testosterone,

1:24:04not just for weight training, but for endurance exercise,

1:24:07so this is one of the reasons why every once in a while,

1:24:09professional cyclists will get popped

1:24:11for performance-enhancing drugs,

1:24:12meaning they'll get caught,

1:24:14and it's not just that they're increasing red blood cells

1:24:16through EPO and things of that sort,

1:24:18oftentimes they're also taking testosterone

1:24:20not because they want to be large

1:24:22or have massively hypertrophied muscles,

1:24:25but because they're injecting testosterone,

1:24:28they don't have to worry

1:24:28about cortisol-induced reductions in testosterone,

1:24:31and they can just clamp,

1:24:32or keep their testosterone levels high,

1:24:34not something I'm recommending,

1:24:35but I'm just justifying the rationale

1:24:38for why an endurance athlete would want to do that at all.

1:24:41So now let's switch over to talking about estrogen,

1:24:45so there are many people

1:24:46who are trying to optimize their estrogen levels,

1:24:48and one of the places where this shows up a lot

1:24:50and I get a lot of questions about is menopause,

1:24:53so menopause, as I mentioned earlier,

1:24:55is this fairly massive reduction in the amount of estrogen

1:24:59that is circulating in one's blood

1:25:01mainly because the ovary

1:25:04is now depleted of some estrogen production of its own,

1:25:08the eggs are not being produced,

1:25:09they've been depleted, et cetera.

1:25:12So menopause is characterized by a variety of symptoms,

1:25:15and it's multifaceted,

1:25:17probably deserves an entire episode on its own,

1:25:20but things like hot flashes, things like mood swings,

1:25:23things like headaches, in particular migraine headaches,

1:25:26there can be a lot of brain fog,

1:25:28it can be very, very disruptive for people.

1:25:30Now, you sometimes hear about andropause,

1:25:32which is thought to be the kind of analog to menopause,

1:25:35but menopause has certain characteristics

1:25:37that make it a very robust phenomenon for most women,

1:25:42whereas for men,

1:25:44andropause is going to sometimes happen, sometimes won't,

1:25:47in fact, without going into the details

1:25:49of the graphs and the data,

1:25:51it's very clear, as I mentioned earlier,

1:25:53that some men maintain levels of circulating androgens

1:25:57that are quite high,

1:25:58even as similar as they were in puberty

1:26:00and their teen years and 20s,

1:26:02well into their 60s, 70s, and 80s

1:26:04if they're optimizing a lot of other things,

1:26:06and probably genetics plays a role as well,

1:26:09whereas some males won't,

1:26:10but within the female population,

1:26:13or population of individuals that have ovaries,

1:26:16there's a very stereotyped and characteristic

1:26:18reduction in estrogen levels

1:26:21as the number of eggs becomes depleted,

1:26:23and that's what we think of as menopause.

1:26:26So what are the various things

1:26:28that one can do for menopause?

1:26:30Well, one of the most common ones

1:26:32is that physicians will prescribe supplemental estrogen,

1:26:36so this is hormone therapy

1:26:37where somebody takes either their oral estrogen

1:26:40or they'll use a patch or a pellet,

1:26:42some way to secrete estradiol into the system,

1:26:45and that has varying success depending on the individual,

1:26:49some people respond very well to it,

1:26:51other people really have challenges with it,

1:26:53and there are a lot of side effects associated with it

1:26:55for some people, not others,

1:26:57in addition, there's a concern always

1:27:00about supplementing estrogen

1:27:01when there's a breast cancer background in the family

1:27:06or there's concern about breast cancer for any reason

1:27:08because a lot of those cancers are estrogen-dependent,

1:27:11and that's why drugs like tamoxifen and anastrozole

1:27:15and drugs that block either aromatase

1:27:18or block, excuse me, estrogen receptors directly

1:27:21were initially developed,

1:27:23you see them a lot on the internet,

1:27:24again, for all the sports folks

1:27:27who are trying to increase testosterone, reduce estrogen,

1:27:30but remember, those drugs were initially developed

1:27:32as ways to prevent estrogen binding to the estrogen receptor

1:27:37as cancer treatments,

1:27:39so I want to be very clear

1:27:40and I've said this many times,

1:27:41we always put it in the caption of each episode, of course,

1:27:44that I'm not a physician, I'm not an M.D.,

1:27:47I don't prescribe anything,

1:27:48I'm a professor and I profess things,

1:27:49I'm here to translate the scientific literature

1:27:51and point to what might be

1:27:52some useful avenues for exploration,

1:27:54but this is just for information purposes,

1:27:56you should definitely talk to your doctor

1:27:58about anything that I'm talking about now

1:28:00or in any episode, for that matter.

1:28:02So if you look at the literature on menopause

1:28:06outside of just standard estrogen therapy,

1:28:10there are some very interesting compounds out there

1:28:12that have been used

1:28:13and that are supported by quality peer-reviewed studies,

1:28:17and again, I'll refer you once again

1:28:19to this amazing website, examine.com,

1:28:21where you can put in essentially any condition

1:28:24or any supplement,

1:28:25and it will point you to the human effect matrix,

1:28:27not animal studies,

1:28:29but human studies that have explored these things.

1:28:32Now, there are a huge variety of them here

1:28:34so I won't go into all of them,

1:28:35but some of the pro-estrogenic compounds

1:28:38that have been shown to be powerful

1:28:42in the context of menopause,

1:28:44as well as other conditions

1:28:46where estrogen is lower than one would like,

1:28:49include a description in some of the literature,

1:28:51I'll get into this in a moment,

1:28:52of something like black cohosh,

1:28:54I think that's the correct pronunciation,

1:28:56it's literally the word black and then C-O-H-O-S-H,

1:29:01and it's very interesting,

1:29:02there are 13 peer-reviewed studies

1:29:05that have reached prominence

1:29:08in the kind of commercial landscape

1:29:10where this substance, black cohosh,

1:29:12has been promoted as a way to increase estrogen,

1:29:15turns out that the effects are consistent

1:29:18but are fairly minor,

1:29:19fairly minor increases in estrogen,

1:29:22so it does seem to be a real effect,

1:29:25it is significant over the placebo effect,

1:29:28but there's also a significant placebo effect

1:29:30in some of these studies as well,

1:29:32so what's interesting when you look at these studies

1:29:35is that many of them were carried out

1:29:38over a period of six-plus months,

1:29:40they're double-blind studies, et cetera,

1:29:42and almost all of them lead to modest increases in estrogen

1:29:46and modest decreases in menopause-related symptoms.

1:29:52Now, a few additional details about these studies,

1:29:56they were generally carried out on women age 45 to 64,

1:30:00in some cases, they look specifically at women

1:30:03that were clinically obese or overweight,

1:30:05although not always,

1:30:07the subject size pools are pretty big,

1:30:09you know, anywhere from 50 to 87,

1:30:12these are decent size, 132 subjects, et cetera,

1:30:16so these look to be like quality studies,

1:30:17and they basically point to the fact that black cohosh

1:30:20can have a modest effect in improving menopause symptoms.

1:30:25The other one is Panax ginseng,

1:30:28so P-N-A-A-X ginseng,

1:30:31has been shown to decrease some symptoms

1:30:33associated with menopause, mostly related to libido,

1:30:37although the other effects were unreliable.

1:30:40Other things, like maca,

1:30:41which is known to increase dopamine actually,

1:30:43had minor effects,

1:30:45things like, the names here

1:30:47are a little hard to pronounce, so forgive me,

1:30:48things like Valeriana officinalis

1:30:53has shown that there can be some improvement

1:30:55in the hot flash symptoms

1:30:57and some of the insomnia associated with that,

1:30:59so that might be worth exploring,

1:31:01again, discuss with your doctor,

1:31:02but these were both 100-subject plus,

1:31:07age 45 to 64 individuals,

1:31:09double-blind placebo-controlled studies

1:31:11that showed significant but modest effects.

1:31:14There was one substance

1:31:16in the gallery of the compounds that was looked at

1:31:21that turns out to be particularly interesting,

1:31:24and this one is also particularly difficult to pronounce,

1:31:27and it's Pueraria mirifica,

1:31:32so I'm going to spell this out for you,

1:31:33it's P-U-E-R-A-R-I-A, Pueraria,

1:31:40mirifica, M-I-R-I-F-I-C-A,

1:31:46and there are four studies on this compound

1:31:49that show, in every case, it to be very potent,

1:31:53in fact, comparable to estrogen therapy,

1:31:56estrogen replacement therapy,

1:31:57in reducing the symptoms of menopause,

1:31:59so this was pretty striking

1:32:01because when you go through these studies

1:32:02and you look again

1:32:03that they seem to be pretty well controlled,

1:32:06as far as I could tell,

1:32:08and they explored a pretty wide subject pool,

1:32:12and it seems that every single one of these studies,

1:32:16when looking side by side at Pueraria mirifica,

1:32:21which is also called,

1:32:22now this is really hard to pronounce, Kwao Krua Kao,

1:32:26I guess that's the name that they use in various countries,

1:32:31that it was comparable to estrogen replacement therapy,

1:32:33so I mentioned this because a lot of people contacted me

1:32:36and said, "What about the insomnia in menopause?

1:32:39"What about the headaches in menopause?"

1:32:41Now, I'm not suggesting you run out

1:32:42and immediately start taking any of these compounds,

1:32:44please talk to your doctor,

1:32:45you know, any hormone-related compound

1:32:48is a serious consideration

1:32:50because of the relationship to breast cancers,

1:32:53but just in general, these compounds are,

1:32:55estrogen and testosterone, are exceedingly powerful

1:32:57in terms of controlling our mental and physical states,

1:33:01and so you want to approach them with caution,

1:33:03but I thought that that one in particular was interesting

1:33:06and for which there are quite a few PubMed-documented,

1:33:10peer-reviewed studies in quality journals.

1:33:13Okay, so now let's talk

1:33:14about the role of specific compounds,

1:33:16some of which, many of which can be taken

1:33:18in supplementation form or extracted from diet and nutrition

1:33:22in order to optimize sex steroid hormones,

1:33:25and again, I just want to emphasize

1:33:27that I'm not suggesting anyone take anything

1:33:29or stop taking anything,

1:33:31this is purely for informational purposes,

1:33:33but some of the data on these

1:33:34is quite striking and impressive.

1:33:39It's very clear

1:33:40that certain collections of nutrients are useful

1:33:45for promoting testosterone and estrogen production

1:33:48in their proper ratios,

1:33:50and those things are what I would call

1:33:52the sort of usual suspects,

1:33:54vitamin D, which is important

1:33:56for so many biological functions,

1:33:58including endocrine functions,

1:34:00zinc, magnesium, et cetera,

1:34:04and if you want to look into this more deeply

1:34:06and you want to understand

1:34:07exactly what the negative effects are

1:34:08of not having sufficient zinc and magnesium,

1:34:10and what those levels might actually be,

1:34:13there's a paper that's available, you can go on PubMed,

1:34:16I can't pronounce this last name, I'm sorry,

1:34:19it looks to me like Wrzosek, but it's W-R-Z-O-S-E-K,

1:34:25I hope I didn't butcher that too badly, Wrzosek et al. 2020

1:34:30in "Endocrinology and Metabolism Review,"

1:34:33so this is a recent paper in a good, peer-reviewed journal

1:34:35that talks mainly about

1:34:37how the hypothalamic-pituitary-adrenal axis

1:34:41and the sex steroid hormones

1:34:43are negatively impacted by deficiencies in magnesium,

1:34:47deficiencies in vitamin D, and deficiencies in zinc,

1:34:50however, that doesn't point to the levels

1:34:53that one should take in order to optimize,

1:34:56so it doesn't say take X amount of zinc

1:34:58or X amount of magnesium or X amount of vitamin D,

1:35:01for that information,

1:35:02because it's so context-dependent and individual-dependent,

1:35:07I highly recommend you go to examine.com,

1:35:09you can put in zinc or magnesium or vitamin D,

1:35:11and they will give you ranges of dosages

1:35:14that are supported by specific studies,

1:35:15again, that information is completely free to you,

1:35:18and it's very useful in figuring that out.

1:35:22I personally have supplemented

1:35:23with zinc, magnesium, and vitamin D for years,

1:35:26but many other people do that as well,

1:35:28and the question is always, how much?

1:35:29And that's why I'm a proponent of getting blood work done

1:35:32because that's how you know

1:35:33whether or not your androgen levels,

1:35:34as well as things like vitamin D levels, et cetera,

1:35:37are sufficiently high,

1:35:39so the takeaway from these studies

1:35:40looking at what deficiencies cause

1:35:43in terms of deficits in testosterone and estrogen

1:35:45really point in the direction of,

1:35:47make sure you're getting adequate zinc, magnesium, and D3

1:35:50unless you want these steroid hormone levels to be reduced

1:35:54for whatever reason.

1:35:55One of the things that's been shown time and time again

1:35:57to have very negative effects on sex steroid hormones,

1:36:00testosterone mainly men, estrogen mainly in women,

1:36:04is opioids.

1:36:06There's this whole issue, of course,

1:36:08of the opioid epidemic, it's deserving of an entire episode,

1:36:11we are going to talk about that with experts in addiction

1:36:15and people that treat pain and so forth,

1:36:19but the opioids dramatically reduce

1:36:22levels of testosterone and estrogen,

1:36:25and they do that mainly by disrupting the receptors

1:36:29on gonadotropin-releasing hormone neurons,

1:36:31these neurons within the hypothalamus

1:36:33that communicate to the pituitary,

1:36:35and in fact, people that take large amounts of opioids,

1:36:38or even take low levels of opioids for long periods of time,

1:36:41will develop all sorts of endocrine syndromes,

1:36:44that's been shown over and over again,

1:36:45gynecomastia, or male breast development in males,

1:36:48disruptions to the ovary in females,

1:36:51it's really a quite terrible situation,

1:36:53so excessive opioids are very problematic

1:36:58for sex steroid hormones,

1:36:59I don't think anyone will have any trouble

1:37:02finding any literature on that,

1:37:03you can just go into PubMed,

1:37:04you can put opioids, testosterone, or opioids, estrogen,

1:37:09but the major effect is actually way up in the hypothalamus

1:37:11to shut down the production of GnRH,

1:37:14the very hormone that stimulates

1:37:15testosterone and estrogen release.

1:37:17Now, there's an entire industry devoted to supplements

1:37:21and various things that people can take

1:37:22to increase testosterone,

1:37:24some of which have scientific data to support them,

1:37:27some of which do not,

1:37:29and some of which have anecdotal support

1:37:31and some of which do not.

1:37:33This ranges so broadly,

1:37:35I mean, things like the material off deer antlers,

1:37:38which is high in, supposedly, IGF1,

1:37:41which is in the growth hormone pathway,

1:37:43all the way to actual consumption of bull testes,

1:37:48you can go on Amazon right now,

1:37:50I certainly don't suggest that you do this,

1:37:51and you can actually buy ground up testes from cows,

1:37:57and you can consume those,

1:37:59now, a lot of that's going to be broken down in the gut,

1:38:01I'm certainly not suggesting you do that,

1:38:02but just the point out this is a huge and vast literature,

1:38:06and it actually dates back hundreds of years

1:38:08even though testosterone wasn't discovered that long ago

1:38:12as a specific hormone molecule

1:38:14and characterized and then resynthesized,

1:38:18it has a huge industry

1:38:20because of the powerful effects that it has,

1:38:22likewise with estrogen,

1:38:23the development of the birth control pill

1:38:25was only made possible by understanding the structure

1:38:28of estrogen and estradiol,

1:38:30and we're going to talk all about birth control

1:38:31and how it works and its influence on various other pathways

1:38:35in a future episode,

1:38:36but there are these supplement compounds

1:38:38that are supported by the scientific literature

1:38:41in terms of their ability to adjust androgens,

1:38:45things like testosterone and dihydrotestosterone.

1:38:48One of the ones that has

1:38:49really good evidence for it is creatine,

1:38:53it's very clear that something about creatine,

1:38:55although the mechanism isn't exactly clear,

1:38:58either increases 5-alpha reductase

1:39:01or makes the testosterone molecule more susceptible

1:39:04to certain enzymatic reactions

1:39:07that leads to increases in DHT,

1:39:09DHT, dihydrotestosterone,

1:39:11as I mentioned in the previous episode,

1:39:13has this dramatic role in creating

1:39:15a kind of masculinization of the brain prenatally,

1:39:19it also defines the primary sex characteristic

1:39:22of the growth of the penis, et cetera,

1:39:24and beyond infancy and early childhood and later in life,

1:39:29it has powerful effects in creating balding,

1:39:31in beard growth, et cetera,

1:39:33and it has a much higher affinity for the androgen receptor

1:39:36than does testosterone,

1:39:39so creatine can increase DHT,

1:39:42which means that if you take creatine

1:39:45and you're very DHT-susceptible,

1:39:47then you might experience some hair loss,

1:39:49this has been heavily debated, does creatine cause baldness?

1:39:52It's going to depend,

1:39:53it's going to depend on how much 5-alpha reductase you have

1:39:55and how prone to hair loss you are,

1:39:58some people can take creatine without any problem

1:40:00in terms of hair loss,

1:40:01some people cannot, they start losing their hair

1:40:04to levels that, at least for them, aren't comfortable.

1:40:07There are a few other things that can increase testosterone

1:40:10and it has to do with the way

1:40:11that testosterone exists in its free and its bound form,

1:40:16so testosterone, the molecule is kind of total testosterone,

1:40:20that's usually what's measured,

1:40:21this is the kind of levels that are typically thrown around

1:40:24of anywhere from 300 to 900 being the kind of natural range,

1:40:27and then supraphysiological,

1:40:29getting up into 1,200, 1,600 range,

1:40:32but testosterone isn't

1:40:34just roaming around free in the blood,

1:40:36at least most of it isn't,

1:40:37most of it is bound

1:40:39to either sex hormone binding globulin, SHBG, or to albumin,

1:40:44they're needed as transporters

1:40:46to get testosterone into cells

1:40:48so that testosterone can have its effects on gene expression

1:40:51as well as other pathways within the cells,

1:40:54so people talk about that the level of free testosterone

1:40:58is really what's important

1:40:59and that you want to optimize free testosterone,

1:41:01that's a little bit of a tricky statement,

1:41:03that's kind of like, it's true,

1:41:07and yet, it's not really reflective

1:41:10of a thorough understanding

1:41:11of how these binding globulins work,

1:41:14remember, these binding globulins

1:41:15aren't there to soak up all your testosterone

1:41:17just to make it hard for you to free up testosterone

1:41:19and you know, make gains in the gym or whatever it is,

1:41:23or have increases in libido,

1:41:24they're there to actually transport testosterone

1:41:26to specific tissues, to shuttle them to specific tissues

1:41:30and to set the rate of bound and unbound testosterone

1:41:34so that's it's not all unbound at once,

1:41:36and you know, it's always interesting

1:41:38to look in the literature

1:41:39and see how everyone wants

1:41:40to free up their testosterone so that it can work,

1:41:42but sex hormone binding globulin

1:41:46can bind up too much testosterone

1:41:47to the point where it's having negative effects on libido

1:41:50or on muscle growth and fat loss and things of that sort,

1:41:53this is true in males and females,

1:41:55or it can be doing exactly what it's supposed to do,

1:41:58which is shuttling testosterone

1:41:59to the proper tissues and organs

1:42:01where it has all these effects, including the brain.

1:42:04So there are supplements,

1:42:08in particular, tongkat ali,

1:42:09which is, it has this other name,

1:42:11it's something called tongkat ali,

1:42:13sometimes it's called,

1:42:14and forgive me that it's hard to pronounce,

1:42:16but Eurycoma longifolia Jack,

1:42:21they always seem to have these names

1:42:23that kind of allude to androgenic features,

1:42:27like I don't know why, longifolia Jack,

1:42:29I don't know, I think it's kind of obvious

1:42:31why that sounds sort of androgenic.

1:42:35This has been shown in several studies,

1:42:37and you can find these on examine.com,

1:42:39or you can go to PubMed if you like, I've looked at these,

1:42:41that it does seem to have some pro-fertility,

1:42:43pro-free testosterone, and subtle aphrodisiac effects,

1:42:49it does also seem to be a slight anti-estrogen,

1:42:52so the reports of this are,

1:42:55people take this anywhere from 400 to 800 milligrams a day,

1:42:58again, I'm not suggesting you do that,

1:42:59but that's kind of what's out there,

1:43:01and there is some decent scientific literature

1:43:03to support the fact that it liberates

1:43:05some of the bound testosterone

1:43:07and allows more free testosterone to be available,

1:43:10some of the reported quote-unquote side effects

1:43:12are things like excessive alertness and insomnia

1:43:15if it's taken too late in the day and so forth,

1:43:17but I encourage you to explore that further if that's,

1:43:21if increasing free testosterone

1:43:22is something that you're interested in doing.

1:43:25Examine.com includes a lot of other things

1:43:29that can increase testosterone,

1:43:31one of the things that's been

1:43:33purported to free up testosterone in the blood

1:43:36are things like nettles, stinging nettles,

1:43:39although I should point out that the literature

1:43:41points to stinging nettle

1:43:42also having some fairly potent effects

1:43:45on the prostate and on the liver,

1:43:47and so it might be a tricky molecule

1:43:49and maybe not an attractive one for people to take.

1:43:52So we talked about creatine, we talked about tongkat ali,

1:43:54it's clear that boron, which is really interesting,

1:43:57believe it or not, I think boron comes from,

1:43:59I think these were like, meteors that landed on Earth

1:44:02and now they extract boron,

1:44:04it's one of these crazy stories that, when you look at it,

1:44:07you go like, "How could that possibly be?"

1:44:08but there's actually, that's how it works,

1:44:11that boron, there's some scientific support

1:44:14for it freeing up more testosterone,

1:44:16and again, freeing up testosterone

1:44:17may be exactly what you want,

1:44:19I just don't think that we should

1:44:20demonize these carrier proteins like albumin and SHBG,

1:44:23in fact, albumin is very important

1:44:25for testosterone to be able to make it into the brain

1:44:28to have some of the pro-androgenic effects

1:44:31on the cognitive effects of testosterone

1:44:33because in both males and females,

1:44:35testosterone can shift these behaviors, like mate-seeking,

1:44:40reductions in anxiety, and so forth,

1:44:43that we talked about before,

1:44:44only by making it into the brain,

1:44:45and there is this thing called the blood-brain barrier,

1:44:48which is fascinating

1:44:49and deserving of an entire episode also,

1:44:51and getting molecules across the blood-brain barrier,

1:44:54even if they're sex steroid hormones, which are lipophilic

1:44:57and can pass through cell membranes, requires carriers,

1:45:00and those carriers often are bound to or include albumin,

1:45:05and so it's not the goal to free up all your testosterone,

1:45:11but getting free testosterone into a range

1:45:13that works for your particular goals and needs

1:45:15is an attractive one,

1:45:17and that's why we're discussing these particular tools.

1:45:19The amounts of boron that people take,

1:45:21and you can find this, again, on PubMed or Examine,

1:45:24but people take a couple grams of it a day,

1:45:26I'm not aware of any specific side effects,

1:45:28but you always, always, always want to examine

1:45:30for the particular side effects

1:45:32and people with different backgrounds and conditions,

1:45:34as we talked about for menopause and estrogen,

1:45:37have to be careful

1:45:38because when you're starting to modulate hormones,

1:45:40you're starting to modulate not just the tissues

1:45:44that thrive on binding of those hormones,

1:45:46but remember, the reason why there's so much breast cancer

1:45:51and there's a reason why there's so much testicular cancer

1:45:53is that any tissue that undergoes rapid reproduction

1:45:57of particular cells,

1:45:58so there's a lot of reproduction of cells

1:46:00in shedding of uterine lining

1:46:01and the reproduction of cells and eggs in the ovary,

1:46:04and in the testes, there's the production

1:46:06of Leydig and sertoli cells,

1:46:09and there's this kind of ongoing production of sperm,

1:46:12that's why those tissues are particularly vulnerable

1:46:15to the development of cancers,

1:46:16and many of those cancers are androgen-sensitive,

1:46:18that's why one of the major treatments

1:46:21for prostate overgrowth or prostate cancer

1:46:23is to give anti-androgenic drugs, okay?

1:46:26It's not just to shut down all things

1:46:29related to being androgenized,

1:46:33it's really about trying to prevent testosterone

1:46:35from encouraging growth of tumors,

1:46:37so I want to really emphasize the caution there

1:46:41because it's easy when thinking

1:46:43about optimizing estrogen and testosterone

1:46:45to just think, oh, more is better,

1:46:47more is definitely not better,

1:46:48and it's not just because they can aromatize

1:46:50or convert into other things,

1:46:52it's because cancers,

1:46:54or any tissue that has a lot of turnover of cells,

1:46:57is going to thrive on androgen,

1:47:00anything that promotes growth

1:47:01is going to thrive on estrogen,

1:47:03remember, brain tissue doesn't turn over that much,

1:47:05there isn't really much production of new neurons,

1:47:07brain cancers happen but they're kind of rare,

1:47:09and when they do happen,

1:47:10they tend to be glial cells,

1:47:11which have a lot of proliferation,

1:47:13glial cells can proliferate,

1:47:14adult neurons don't create more of themselves,

1:47:17they don't create more neurons,

1:47:18in general, except in a few places in the brain and body,

1:47:21so any tissue that recycles itself is prone to cancers,

1:47:27and those tissues thrive on androgens and estrogens

1:47:31to create more tumor,

1:47:32so you have to be careful

1:47:34anytime you're modulating hormones,

1:47:35especially androgens and estrogens,

1:47:38and in my scouring of the literature

1:47:40and looking at kind of what's out there

1:47:41and what people are talking about,

1:47:43and I also mean in the scientific literature,

1:47:46one of the things that is new to me, anyway,

1:47:49probably not new to a lot of the gym rats out there,

1:47:54or the people that spend a lot of time on YouTube videos

1:47:56talking about androgens,

1:47:58are these, forgive me for butchering the name again,

1:48:01are these ecdysteroids,

1:48:03so ecdysteroids are molecules

1:48:08that come from things like spinach, believe it or not,

1:48:12that have a lot of similarity to the cholesterol molecule,

1:48:16the one that's being discussed a lot out there right now

1:48:19is something called turkesterone,

1:48:21I wish I knew why it was called turkesterone,

1:48:23someone tell me why it's called turkesterone,

1:48:25does it have anything to do with turkeys?