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How Ice Baths Impact Testosterone
Contradictions in Testosterone Research
Studies of ice baths used for recovery after exercise typically indicate that cold water immersion will blunt gains and reduce testosterone levels in men -- at least in the short term. For example, when men sat in cold water right after heavy squats, their testosterone was about 10% below its starting level an hour later (Earp et al. 2019). Military divers who spent nine hours in 4°C water came out with significantly less testosterone immediately after their dive, compared to when they started (Kelly et al. 2022).
The problem is that every single study measuring testosterone suppression by cold fails to exhibit understanding of the mechanisms by which cold exposure results in testosterone gains.
Mitochondrial Origins of Sex Hormones
Testosterone synthesis originates in mitochondria, where an enzyme called P450scc converts cholesterol into a sex steroid called pregnenolone. All sex hormones, including testosterone, estradiol, and non-sex steroids like cortisol, are derived from pregnenolone (Miller 2013). Therefore, more testosterone requires more pregnenolone, which requires more mitochondria. The human body responds to cold stimulation by producing new mitochondria for cold thermogenesis in a process called mitobiogenesis, and it takes time.
The time-lag effect explains how short-term studies show no immediate gains from ice baths after exercise, whereas long-term cases often show enormous gains. For example:
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A 47 year old Polish man who spent 50 days of winter living in an unheated igloo on a frozen river in Rovaniemi, Finland. He measure total testosterone gains of 60%, from 673 to 1,077 ng/dL despite getting only an average of 3 hours of sunlight a day (Teległów et al. 2022).
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When 22 young British men embarked on a 42-day Antarctic expedition, their average total testosterone increased from 14.0 to 17.3 nmol/L (404 to 499 ng/dL) and free testosterone from 288 to 350 pmol/L (Woods et al. 2015).
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A new study out of Czechia put trained, lean young male athletes through a 5-day program of intensive exercise and cold water (2°C) immersion. They measured no change in testosterone levels until one week later, when they noticed total testosterone in the group jumped by an average of 56% (Jaklová Dytrtová et al. 2026).
The Japanese Study from Sakamoto
The first clue that simplistic studies of ice baths for recovery were failing to capture the real relationship between cold and male testosterone was the Sakamoto et al. (1991) study that showed a big improvement in total testosterone and luteinizing hormone results from cold stimulation before exercise (precooling), rather than after.
This Japanese group did something no other research studied had attempted before. When they reversed the order of the cold stimulation and the exercise, they discovered that precooling the body prior to exercise resulted in a big boost to both total testosterone and luteinizing hormone, compared to the traditional approach of using cold plunge for recovery.
Joe Rogan has been posting about ice baths since 2021. More than anyone else, he popularized the practice of precooling exercise to provide a short-term testosterone boost. New research shows the ice bath + exercise also supports long-term testosterone gains in men.
When I boosted my own testosterone from mid-700's to 1180 ng/dL, I was practicing precooling, so I wrote about my results in What Happened to My Testosterone... and I called attention to the distinction between precooling and ice baths for recovery after exercise. It was Dec 2022 when Joe Rogan featured an Instagram post of mine based on my article during his podcast episode #1906 with David Goggins and soon afterwards, dozens of people started sending me their lab reports showing similar results.
What got overlooked is that none of these successful case studies, including mine and my readers, were of the short-term type reported in the ice bath for exercise recovery literature. In my case, it took me four months after starting my program before I retested and the fastest testosterone ramp I've ever seen still took 30 days.
Cold Plunge Therapy Boosts Testosterone via Mitobiogenesis
Low testosterone, diagnosed as hypoandrogenism, commonly occurs in older men as mitochondrial function decline with age. Presumably, aging causes the testis to lose the ability to produce adequate levels of testosterone, despite normal or unchanged levels of luteinizing hormone (Cohen et al. 2020). Nonetheless, my results and those of other men in their 50's and 60's calls the common experience into question -- especially since low testosterone is increasing observed in younger populations.
In my article Why is Testosterone So Low? I speculated that the principal reason for low testosterone among young men is mitochondrial impairment. Considering the indispensable role of mitochondria in testosterone synthesis, and the epidemiological data that is consistent with record high rates of metabolic dysfunction, it makes sense that low mitochondrial function in young men would be the cause of low testosterone. It follows that the remedy is rejuvenation of the mitochondria.
Although exercise stimulates mitobiogenesis. Hydrogen therapy will, too (Cui et al 2024 [mice], Luo et al. 2022 [rats]). Nevertheless, as I explained in Ice Baths for Mitochondrial Therapy, the best way to boost mitochondrial function is with cold plunge therapy.
The master regulator of mitochondrial biogenesis is a cold-induced protein called PGC-1α. In mice, cold exposure raises PGC-1α in brown adipose tissue (BAT, or brown fat) and in skeletal muscle -- the two tissues that are dense in mitochondria and most responsible for cold thermogenesis -- and switches on mitochondrial genes (Puigserver et al. 1998). In humans, 10 days of cold acclimation increases brown fat activity (van der Lans et al. 2013) and boosts insulin sensitivity (Hanssen et al 2015). Moreover, when runners immersed one leg for 15-minutes in 10°C water, PGC-1α gene expression in the cold leg was higher when compared to the warm leg (Ihsan et al. 2014). Other markers of mitobiogenesis also increased when the cold immersion was repeated after every running session for four weeks (Ihsan et al. 2015).
The process of mitobiogenesis takes time, just like it takes time to grow new muscle. Imagine a study that sought to determine whether weight training increases strength. If the researchers put athletes through a strenuous workout, and then measured their maximum strength, would it be any wonder if the scientists concluded that exercise makes the athletes weaker?
But everyone understands that exercise does not give immediate strength benefits, and that a post-stress measurement is not a valid measure of hormetic stress. Neither are measurements of testosterone immediately following cold plunge a valid assessment of the impact of cold on sex hormones. Only studies that extend for longer periods of time, like the 2026 Czech study, can be expected to show consistent benefits -- with one exception.
How Women Get an Instant Testosterone Bump from Cold
In men, the vast majority of testosterone is made in the Leydig cells of the testes. Mitobiogenesis in brown fat and muscles is insufficient to power testosterone synthesis, so men must wait for the new mitochondria they produce in brown fat to be exported to the bloodstream, travel to the testes and later be imported by the Leydig cells. The phenomenon is called "intercellular mitochondrial transfer" (Borcherding & Brestoff 2023). It has been observed for heart muscles damaged from ischemic injury, but never studied in Leydig cells and it was unknown to me until Columbia University Professor Martin Picard, PhD explained it to me in our podcast A Master Class in Mitochondria, but until someone says it's impossible I think it's a plausible explanation for improving mitochondrial function in the testes.
Women's body work different.
In women, about three-quarters of total testosterone is produced in skin cells, fat cells (Chen et al. 2002), and adrenal glands (Burger 2002). Only about one-quarter is produced in the ovaries. Therefore, women can get an immediate boost in testosterone from cold stimulation. One study of female undergraduates showed women's saliva testosterone rose an average of 15% within 10 minutes of dipping just one hand in 2°C water (Archey et al. 2019). Women can get long-term benefits too, as the documented case studies of Pamela Butler and Eloise DeSouter suggest -- but it's interesting to note that the short-term testosterone research on athletes using ice baths after exercise is almost exclusively done with men. Because low testosterone levels in women can cause heart deficits, depressive symptoms, muscle deterioration, low libido, cognitive impairments & reduced overall well-being (Al-Azzawi & Palacious 2009), women would do well to experiment with cold plunge therapy on their own, rather than wait for new clinical trials to confirm what existing case studies and surveys already suggest (Pound et al. 2024).
Resolving the Ice Bath Testosterone Controversy
There is no single, simplistic relationship between cold therapy and testosterone. Rather, outcomes are determined by three factors, in combination:
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Sex. Women get a temporary boost from cold stimulation, and long-term benefits from mitobiogenesis.
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Timing. In men, measurements immediately following cold exposure are likely to show a drop in total testosterone levels. In the short-term, doing some light exercise to restore blood flow and rewarm the testes may show a boost in testosterone.
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Consistency. Long-term benefits rely on mitobiogenesis to boost conversion of cholesterol to pregnenolone, and mitobiogenesis requires a consistent application of hormetic stress over a period of 10-14 days.
WARNING. Too much cold, or too much exercise, can tip the balance of hormesis from eustress into distress. When mitochondria are overtaxed, they will not be available for mitobiogenesis. Rather, they will likely redirect energetic resources from growth to survival. Additionally, other factors such as magnesium or zinc insufficiency, a long-term history of testosterone replacement therapy, or medications that interfere with mitochondrial function can frustrate attempts to achieve higher testosterone levels via cold plunge therapy.
A practical cold plunge testosterone protocol
This routine is adapted from How to Boost Testosterone: Cold Plunge Protocols. Treat it as a point of departure for your own N=1 experiment, not medical advice or a personal recommendation. Also, review Contraindications to Cold Plunge and our ice bath safety guide first. Anyone with uncontrolled high blood pressure must consult with a clinician prior to cold plunging.
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Plunge neck-deep for 2 to 4 minutes, about five days a week, in water cold enough to trigger a gasp. Beginners may start around 50°F and work down toward 34 to 36°F. Tubs that are electrically grounded to Earth (like Morozko) will enhance mitochondrial function (Giulivi & Kotz 2025) and provide an extra measure of electrical safety. If your cold plunge lacks Morozko Minerals, then supplement with magnesium, zinc, potassium, and copper regularly.
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Rewarm with light movement, about 3 minutes of exercise for every one minute of cold. Outdoors in sunlight is ideal. A steel mace, push-ups, kettlebells, brisk walking, rowing, jumping jacks, gentle yoga, and squats are all good choices.
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Train. When the blood has been restored to your limbs, you might decide to lift heavy weights or go hard with sport-specific training.
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Be consistent and patient. Mitochondrial gains take two weeks, not a single session. If you've been taking testosterone replacement therapy (TRT) and you're trying to quit or taper off, you'll need more time to rebuild the capacity for steroidogenesis in your testes.
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Sauna after exercise. Do not sauna prior to your cold plunge. Save your sauna for after your exercise.
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Sleep. Testosterone is made at night, while you are sleeping.
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Test. Get morning labs (total and free testosterone, LH, SHBG) before you start, and retest after 8 to 12 weeks at the same lab and time of day.
Uncommon Testosterone summarizes many of the experiences described in my first book, Uncommon Cold, and dives deeper into the science of cold plunge therapy for testosterone synthesis.
References
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Borcherding N, Brestoff JR. The power and potential of mitochondria transfer. Nature. 2023 Nov 9;623(7986):283-91.
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Giulivi C, Kotz R. Earthing effects on mitochondrial function: ATP production and ROS generation. FEBS Open Bio. 2025.
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