How to Optimize Testosterone & Estrogen | Huberman Lab Essentials
Date: 2025-02-20 | Duration: 00:32:40
Transcript
0:00 Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I’m Andrew Huberman, and I’m a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford. Before we begin today, I just want to acknowledge that if you’re watching this on YouTube, yes, I have a bandage on the left side of my face. I was trying to cook something for Costello and I got burned. It was a cooking accident. I’m fine, no need to dwell on it. We can move on, but I just wanted to let you know everybody’s going to be okay. He got a great meal; I got a burn and a great meal.
0:30 Today we’re going to be talking about hormone optimization, and we’re mainly going to be focusing on estrogen and testosterone and their derivatives. Now, estrogen and testosterone and their derivatives are what we call sex steroids, but I just want to emphasize that estrogen and testosterone are present in everybody; it’s their ratios that determine their effects. Today we’re going to talk about how specific types of exercise, particular patterns of cold exposure, as well as particular patterns, believe it or not, of breathing can impact sex steroid hormones, both estrogen and testosterone.
1:00 One of the first things to understand if you want to optimize your hormones is where they come from. There are a lot of different glands in the body that produce hormones, but when we’re talking about the sex steroid hormones estrogen and testosterone, the major sources are ovaries for estrogen and the testes for testosterone, although the adrenals can also make testosterone. Now, there are also some enzymes—enzymes are things that can change chemical composition—and the enzymes that we’re going to talk about today are the aromatases. Mainly, the aromatases convert testosterone into estrogen. So in a male, for instance, that has very high testosterone, some of that is going to be converted into estrogen by aromatase.
1:30 The important thing to know is that prepubertal females make very little estrogen. When we talk about estrogen, we mainly talk about estradiol, which is the most active form of estrogen in both males and females. So, prepubertal females have very low levels of estrogen. During puberty, levels of estrogen, AKA estradiol, basically skyrocket. Then across the lifespan, estrogen is going to vary depending on the stage of the menstrual cycle. But as one heads into menopause, which typically takes place nowadays somewhere between age 45 and 60, levels of estrogen are going to drop, and then postmenopause, levels of estrogen are very low as well.
2:00 Testosterone will fluctuate across the lifespan. Testosterone is going to be relatively low pre-puberty in males. During puberty, it’s going to skyrocket, and then the current numbers are that it drops off at about a rate of 1% per year. Let’s talk about other sources of these hormones, and then it will make clear what avenues you might want to take in order to optimize these hormones. The other glands and tissues in the body that make these hormones, testosterone and estrogen, as I mentioned briefly, are the adrenals. So the adrenals, right on top of the kidneys, and the release of these steroid hormones from the adrenals—in particular testosterone and some of its related derivatives—are mainly activated by competition.
2:30 It’s pretty interesting; there’s a lot of evidence in animals and humans that competitive scenarios, at least short-lived competitive scenarios, can liberate testosterone from the adrenals. Let’s talk about competition because it turns out that competition is a powerful influence on the sex steroid hormones, and the sex steroid hormones powerfully influence competition. Most people don’t realize this, but most males of a given mammalian species never get to reproduce. In fact, they never even get to have sex at all. We don’t often think about that, but testosterone plays a powerful role in determining which members of a given species will get to reproduce, which ones of that species will actually get access to females.
3:00 Here I’m not talking about humans specifically, but it’s well known in species like elephant seals, in species like antlered animals and rams, for instance, that the higher levels of testosterone correlate with access to females. Now, one interpretation of this is that the females are detecting which males have high testosterone and selecting them—they’re more receptive to them—but it’s actually more so that the males that have higher testosterone forage further and will fight harder for the females. This is really interesting because there’s very good evidence now that testosterone can reduce anxiety, promote novelty seeking, and promote competitive interactions.
3:30 Before you leap too far with this in your mind and think about all these human behaviors, just stay with me because there’s a little bit of biology here that makes it all make sense, and it turns out to be pretty simple. We have a brain region called the amygdala. In Latin, that just means almond, but the amygdala is most famous for its role in fear. We hear a lot about fear and the amygdala, but the amygdala is really involved in threat detection; it sets our thresholds for anxiety and what we consider scary or too much. Testosterone secreted from the gonads and elsewhere in the body binds to the amygdala and changes the threshold for stress.
4:00 I’ve said before on previous versions of this podcast and on other podcasts that testosterone has this incredible effect of making effort feel good, but what I was really referring to is the fact that testosterone lowers stress and anxiety. In particular, in males of a given species, testosterone increases generally lead to more foraging, more novelty seeking, increases in libido, and increases in desire to mate. So it is the case that increases in testosterone promote competitive and foraging-type behaviors in humans and in non-human mammals, but it’s also true that competition itself can increase androgens such as testosterone.
4:30 Some people have come to the conclusion that if you win, your testosterone goes up, and if you lose, your testosterone goes down, and to some extent that’s true. But that’s not a direct effect on the gonads; that’s actually mediated by the neuromodulator dopamine. We talked about dopamine in the episode on motivation and drive, and dopamine and testosterone have a remarkable interplay in the body. Dopamine is actually released in the brain in ways that have the pituitary—this gland that sits over the roof of your mouth—release certain hormones that then go on to promote the release of more testosterone. Indeed, winning promotes more dopamine and later more testosterone.
5:00 However, in the short term, just competing increases testosterone independent of whether or not you win or lose. So testosterone is driving the seeking of sex, and estrogen is promoting the actual act of sex from females—so-called receptivity, consensual receptivity. In males, it’s interesting to point out that testosterone is promoting seeking of sex, but it’s also estrogen in males that’s important for libido. If estrogen levels are brought too low, then men will completely lose their libido. So it’s not simply the case that high levels of testosterone produce a lot of sex and mating behavior and low levels of estrogen are good across the board. You actually need both in both males and females.
5:30 It’s just that in females, the testosterone levels are always going to be lower than the estrogen levels, and in males, the estrogen levels are always going to be lower than testosterone levels. Just as there are behaviors that can increase testosterone, there are behaviors that can decrease testosterone, and one of the most well-characterized ones in humans is becoming a parent. Expecting fathers have an almost 50% decrease in testosterone levels, both free and bound testosterone. It turns out that these effects of reduced testosterone, increased estradiol, and reduced cortisol can all be explained by an increase in prolactin. It is a well-known phenomenon that testosterone is going to drop, prolactin is going to increase, and estradiol is going to increase in males and females that are expecting children.
6:00 The other behavior that markedly reduces testosterone in both males and females, and markedly reduces the desire for seeking sex and sex itself, is illness. Many of you might say, “Well, duh, when people feel sick, they don’t feel like seeking out mates; they don’t feel like having sex.” But have you ever wondered why that actually is? Well, it turns out that it can be explained by the release of what are called inflammatory cytokines. Cytokines are related to the immune system; they travel in the lymph and in the blood and they attack invader cells like bacteria and viruses. Under conditions of illness, we make a lot of different cytokines. Some of them are anti-inflammatory, but some of them are pro-inflammatory.
6:30 The best-known example of a pro-inflammatory cytokine is IL-6. It’s known that IL-6, when injected into individuals, will decrease the desire for sex and eventually will reduce levels of testosterone and estrogen independent of feeling lousy. Now, IL-6 doesn’t just travel to the gonads and shut down the gonads; it actually has ways to interact with some of the receptors that the steroid hormones estrogen and testosterone bind to and impact those receptors so that the sex steroid hormones can’t have their effect. In short and put simply, inflammatory cytokines like IL-6 are bad for sex steroid hormones.
7:00 One of the main behaviors that’s been shown to be associated with poor levels of estrogen relative to age-matched controls for people with ovaries, or lower levels of testosterone compared to age-matched controls for people with testes, is apnea. What is apnea? Apnea is under-breathing or mainly cessation of breathing during sleep. People are holding their breath and then they’ll suddenly wake up. People who are dramatically overweight also suffer a lot from apnea during sleep, and it’s well established that going into deep sleep and getting the proper patterns of slow-wave sleep and REM sleep are important for hormone optimization.
7:30 Breathing itself can be adjusted in the daytime waking hours in ways that can powerfully impact sleep, reduce incidence of sleep apnea, and also help to optimize various hormones. Even just by breathing in particular ways while awake, believe it or not, being a nasal breather and avoiding being a mouth breather can actually positively impact hormones, and in particular the hormones testosterone and estrogen. The way that it does that is by making you a better sleeper, which allows you to produce the appropriate amounts of testosterone and estrogen. But it does that in part through indirect mechanisms because deep sleep supports the gonads—the ovaries and the testicles—and the turnover of cells and the production of cells.
8:00 Remember, in the ovary, particular cells and the egg follicles themselves make estrogen. In the testicle, the Sertoli cells and the Leydig cells are important for the formation of sperm and for testosterone, respectively. So what does this all mean? This means we have to be breathing properly to get your breathing and sleep right so that your sleep can actually be deep enough and you’re not entering apnea states. Getting proper sleep can really offset all the reductions in testosterone and estrogen and reductions in fertility that occur if we don’t get enough sleep. But seldom is it discussed how sleep actually adjusts things like testosterone and estrogen, and it does it by modifying cortisol.
8:30 The molecule cholesterol can be converted into testosterone or estrogen, but there’s a competition whereby the cholesterol will turn into cortisol and not testosterone, or it’ll turn into cortisol and not estrogen, if stress levels are too high. The simple version of this is getting your breathing right during the waking hours, meaning primarily—unless you’re working out really hard or there’s some other reason why you’re eating or speaking that you need to be breathing through your mouth—you should be a nose breather. There’s really good evidence for that now. In sleep, you also want to be a nose breather because that’s