The Science of How to Optimize Testosterone & Estrogen

High-Level Overview

In this Huberman Lab Essentials episode, Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford, walks through how the sex steroid hormones testosterone and estrogen work and how everyday behaviors can raise, lower or rebalance them. He starts with a key reframe, that "estrogen and testosterone are present in everybody. It's their ratios that determine their effects," and then explains where these hormones come from, how competition, parenting and illness change them, and why sleep, breathing, light and temperature act as foundations for hormone health before supplements even enter the picture.

The tone is educational and mechanistic, with Huberman repeatedly insisting that understanding the underlying biology will help listeners use the tools more wisely. He opens with a light moment about a cooking burn on his face, then moves steadily from basic endocrinology to practical protocols, ending with supplements, prescription options and a strong caution that more is not better. The episode flows from science to behavior to protocols, with plenty of safety caveats along the way.

The Discussion Explores:

• Where testosterone and estrogen come from, including the role of aromatase and how levels change with age
• How competition affects testosterone through the amygdala and dopamine
• Why both hormones matter in both sexes, including estrogen's role in male libido
• Behaviors and states that lower testosterone: expecting a child, prolactin and illness-related cytokines
• Sleep apnea, nasal breathing and the cortisol competition for cholesterol
• Morning light, avoiding night light, and the dopamine link to reproductive hormones
• Cold exposure, heavy resistance training and why lifting should come before cardio
• Menopause, supplements such as tongkat ali and Fadogia agrestis, HCG, and the need for blood work

Deep Dive into Main Ideas

Where Sex Hormones Come From

Huberman explains that the main source of estrogen is the ovaries and the main source of testosterone is the testes, although the adrenal glands, which sit on top of the kidneys, can also make testosterone. Enzymes called aromatases convert testosterone into estrogen, so in a male with very high testosterone, some of it will be converted to estrogen. When he talks about estrogen, he mainly means estradiol, the most active form in both sexes.

He sketches the lifespan picture. Estrogen is very low in girls before puberty, skyrockets during puberty, varies across the menstrual cycle, then drops as people head into menopause, which he says now typically occurs between 45 and 60, and stays very low afterward. Testosterone is low in boys before puberty, skyrockets during it, and then, by current numbers, declines about 1 percent per year.

Competition, the Amygdala and Dopamine

The adrenal release of testosterone is strongly triggered by competition. Huberman notes that in many mammal species, such as elephant seals and antlered animals, most males never reproduce, and higher testosterone correlates with access to females, not so much because females select for it but because high-testosterone males forage further and fight harder. Testosterone binds to the amygdala, the brain's threat-detection hub, and raises the threshold for stress and anxiety. That is what he means when he says testosterone has "this incredible effect of making effort feel good." It also increases novelty seeking, foraging and libido.

The relationship runs both ways. Competing, win or lose, increases testosterone in the short term. The popular idea that winning raises testosterone and losing lowers it is partly true, but Huberman says that effect is mediated by dopamine, which prompts the pituitary to release hormones that promote more testosterone.

Both Hormones Matter in Both Sexes

Huberman describes testosterone as driving the seeking of sex and estrogen as promoting sexual receptivity in females. But he stresses that males need estrogen too: if estrogen is driven too low, men can completely lose their libido. The goal is not maximum testosterone and minimum estrogen; both are needed in everyone, with females always having lower testosterone than estrogen and males the reverse.

Some behaviors lower testosterone. Expecting fathers show an almost 50 percent drop in free and bound testosterone, and this, along with rises in estradiol and falls in cortisol, can be explained by increased prolactin. Illness also lowers testosterone, estrogen and sex drive, which he attributes to pro-inflammatory cytokines such as IL-6. Injected IL-6 reduces the desire for sex and eventually hormone levels, partly by interfering with the receptors that sex hormones bind to. In short, inflammatory cytokines are bad for sex steroid hormones.

Sleep Apnea, Nasal Breathing and Cortisol

One of the behaviors most associated with low estrogen or low testosterone compared with age-matched peers is apnea, the cessation of breathing during sleep, which is common in people who are significantly overweight. Deep slow-wave and REM sleep support the ovaries and testes and their production of cells, including the egg follicles that make estrogen and the Sertoli and Leydig cells involved in sperm and testosterone. Sleep also works through cortisol: cholesterol can be converted into testosterone or estrogen, but under high stress it is diverted into cortisol instead.

His practical advice is to be a nasal breather whenever you aren't eating, speaking or exercising at maximum effort, both awake and asleep. People with severe apnea may need a CPAP machine. For others, the best way to improve nasal breathing is to practice it, especially during cardiovascular exercise; the sinuses dilate over time, and he says people often end up producing more output than when breathing through the mouth. He lists the benefits as reduced apnea, more carbon dioxide offloading, greater lung capacity, wider sinuses and even cosmetic effects, which together lower cortisol and indirectly support healthy testosterone and estrogen ratios.

Light and the Dopamine Connection

Huberman argues that light, dopamine and hormones are tightly linked. When dopamine is high, the hypothalamic-pituitary axis releases more gonadotropin-releasing hormone, luteinizing hormone and follicle-stimulating hormone, which stimulate estrogen and testosterone production. His protocol is to get two to ten minutes of bright light in your eyes early in the day, ideally from sunlight, without sunglasses unless needed for safety; prescription glasses and contacts are fine, and bright artificial light can be used if sunlight is not available. This times the cortisol pulse to the early day and raises dopamine.

Equally important is avoiding bright light in the middle of the night, which he says suppresses dopamine and, in turn, testosterone. He emphasizes that you cannot meaningfully talk about supplements or diet for hormones until breathing and light-viewing behavior are right.

Temperature and Exercise

Huberman notes that temperature, day length and sunlight are naturally linked, and that there is growing interest in using cold, such as ice baths and cold showers, to support sex hormones. Cold causes blood vessels to constrict, followed by a rebound dilation that sends more blood to the gonads. He is careful to say it is not known whether cold and heat directly change hormone production; they likely act indirectly through blood flow and neural activity.

On exercise, the more mechanistic studies suggest heavy weight training, but not training to failure, produces the greatest increases in testosterone, in the range of a one-rep maximum up to roughly six to eight repetitions, in both males and females, with effects lasting about a day and sometimes up to 48 hours. Order matters when lifting and endurance work are done in the same session: doing endurance activity first reduced testosterone during the subsequent weight session, so he recommends moving heavy loads first and doing cardio afterward. When done on separate days, the order did not seem to matter. He adds that high-intensity interval training and sprinting somewhat mimic the neural activity of heavy lifting.

Menopause and Estrogen Therapy

Menopause brings a large drop in circulating estrogen as the ovaries' supply of eggs is depleted, with symptoms such as hot flashes, mood swings, migraine headaches and brain fog. Physicians commonly prescribe hormone therapy as oral estrogen, a patch or a pellet. Huberman says results vary widely: some people respond well, while others have challenges and side effects. He flags particular caution for anyone with a family history of breast cancer, because many breast cancers are estrogen-dependent, which is why drugs like tamoxifen and anastrozole that block estrogen receptors or aromatase were developed.

Supplements, Opioids and Prescription Options

Huberman calls vitamin D, zinc and magnesium the usual suspects for supporting healthy hormone production. He warns that opioids have repeatedly been shown to dramatically reduce testosterone and estrogen by disrupting receptors on gonadotropin-releasing hormone neurons, leading in long-term users to problems such as gynecomastia in males and ovarian disruption in females.

Among supplements, he discusses tongkat ali, also known as Eurycoma longifolia, which studies suggest has some pro-fertility, free-testosterone-boosting and subtle aphrodisiac effects, along with slight anti-estrogen activity, reportedly taken at doses in the hundreds of milligrams per day; he notes reported side effects like excessive alertness and insomnia if taken late, and stresses he is not recommending a dose. He also describes Fadogia agrestis, which the literature he found suggests can raise luteinizing hormone and thereby testosterone or estrogen, but whose side effect profile has not been well documented. For prescription options, he explains that HCG, human chorionic gonadotropin, mimics luteinizing hormone and is used to boost fertility, sperm production and ovulation. It was originally collected from pregnant women's urine, which he says once had a black market.

Caution: More Is Not Better

Huberman repeatedly emphasizes caution. Tissues that constantly regenerate, such as the uterine lining, ovaries, testes and prostate, are especially vulnerable to cancers, many of which are hormone-sensitive, which is why anti-androgen drugs are used for prostate cancer. As he puts it, "more is definitely not better." Supplements, he adds, generally have far subtler effects than directly injecting hormones. Because hormones operate through negative feedback, pushing testosterone too high can shut down luteinizing hormone and natural production, and altering estrogen can disrupt the delicate menstrual cycle, in which luteinizing hormone peaks mid-cycle around ovulation. He strongly recommends blood work before and during any hormone-modifying protocol, cycle tracking for people who ovulate, and monitoring testosterone, DHT, estradiol and LH for males.

Conclusion

Huberman's core message is that testosterone and estrogen are both essential for everyone, that their balance matters more than their absolute levels, and that the nervous system drives the endocrine system in predictable ways. The strongest levers are foundational behaviors: nasal breathing and good sleep to limit cortisol and apnea, bright morning light and darkness at night to support dopamine, and heavy lifting done before cardio. Cold exposure may help indirectly, and certain supplements like tongkat ali and Fadogia agrestis show some evidence, but they come with unknowns and should be paired with blood work. Throughout, he urges caution, reminding listeners that hormone optimization is about healthy ratios within normal ranges, not simply pushing numbers higher.

This is a summary of "The Science of How to Optimize Testosterone & Estrogen" from Huberman Lab, giving you the GIST so you can decide if you want the REST. Listen to the full episode.