Can cold stimulation boost testosterone in both sexes?
Summary
Cold exposure stimulates production of neurotransmitters and sex hormones.
In men, precooling exercise with an ice bath can provide a significant boost in testosterone & luteinizing hormone, result in long-lasting health benefits, slow ageing, increase libido, and improve sexual & reproductive health.
Studies of cold therapy & testosterone in men by far outnumber those in women -- despite the fact that testosterone is more abundant than estrogen in the bodies of both.
Low testosterone in women can result in health deficits, including low libido.
There are no FDA-approved testosterone therapies for women, and research on the effects of cold water therapy is absent.
Nonetheless, a cold pressor study suggests women can benefit, too.
Cold plunging for hormonal health
One of the most popular articles in the Journal of the Morozko Method is What Happened to my Testosterone After Using Ice Baths to Treat my Prostate. In that article, I explained how my testosterone increased from the mid-700's to nearly 1200 ng/dL when I started ice baths followed by rewarming exercises. After two years, my testosterone levels are still over 1000 ng/dL, which is super high, considering I'm in my mid-50's. Moreover, Morozko Forge co-founder Jason Stauffer boosted his testosterone levels from the 500's to almost 1000 ng/dL, and I've heard from at least half a dozen other men who have made similar gains. For example, one reader in his mid-40's wrote to tell me that he's boosted his total testosterone from 156 ng/dL to over 1400 ng/dL by eating a low carb diet and doing regular ice baths followed by red light -- so my experience is not unique.
I've already published a follow-up article called The Prostate Protocol that goes into greater depth about using cold plunge therapy and a ketogenic diet to manage cancer risks and inhibit tumor growth. What's still missing is an overview of the science of cold exposure therapy and testosterone -- including a description of whether women can also benefit in the same way men can. And part of the reason I haven't written that article yet is because there are so few studies available from which to draw.
The science of cold therapy for testosterone is almost exclusively focused on young male, elite athletes. While their experience may be instructive, the extent to which is applies to older men, and all women, is still in question. With that caveat in mind, the athlete studies support the results I and others have enjoyed, and there is a least one study that suggests they may be generalizable to women, too.
Cold plunge therapy for testosterone in men
Cycling & weightlifting
Since the breakthrough Japanese study (Sakamoto et al. 1991) established that cold stimulation before cycling boosts natural testosterone production in men, and that cold after exercise suppresses testosterone levels, there have been several follow up studies. For example, a study of American young men who lift weights at least twice a week compared testosterone levels resulting from two post-work out recovery regimes: 1) cold water immersion (CWI), and 2) passive recovery. Those who practiced cold recovery experienced lower post-workout testosterone levels, compared to those who did not (Earp et al. 2019). These results corroborate several others that suggest cold water immersion after exercise will mute anabolic gains from resistance training. In other words, if you're going to use an ice bath after exercise to reduce your muscle soreness and speed recovery, it's best to wait several hours after your workout, so you don't cut your testosterone levels. To maximize your gains, precool your workout by doing your cold exposure prior to your workout.
Rugby
A study of 12 male rugby players examined the effects of precooling with whole-body-cryotherapy (WBC) on subsequent exercise performance and salivary testosterone. Researchers noticed a significant boost in jumping velocity that is consistent with studies I cited in Precool Your Workout. Plus, they measured an increase testosterone among those who completed the cryotherapy prior to exercise (Partridge et al. 2022). The data is confused by large uncertainty bands, and the fact that those subjects in the randomized control group started with higher blood serum testosterone than those in the cryotherapy group. Nonetheless, two hours after completing precooling and jump testing, the testosterone in the cold-treated group caught up to the control group -- mostly because the control group dropped and the cold-treated group increased. Because the study was conducted in the afternoon, between the hours of 1P- 6P, we would expect the control group testosterone to fall in accordance with the normal diurnal variation in male testosterone levels, which typically reach their nadir in the evening before sleep. The fact that the precooled group boosted testosterone at a time of day when it is expected to decline corroborates the previous findings in Sakamoto et al. (1991).
A longer study of Italian rugby players tracked changes in testosterone levels resulting from seven straight days of twice-daily cold air cryotherapy. Players did three and a half minutes at -140°C after morning and evening workouts. The cryotherapy showed no effect on testosterone levels after the first day. However, after the full week of two-a-day treatments, the players' average saliva testosterone levels jumped nearly 50%, while 17β-estradiol dropped by 25% (Grasso et al. 2014). Because they were doing cryo twice a day, they were alternating it with exercise, which makes the study hard to interpret with regard to which came first: the exercise or the cold exposure.
What about older men?
Every study of precooling and testosterone involves young, male athletes -- exactly the group in whom we would expect high testosterone levels to begin with. To date, the only data regarding cold exposure, exercise, and testosterone in middle-aged men is what my readers and me have generated. This reality is ironic, given that testosterone levels typically decline with age, and low testosterone among men older than 40 is increasingly common.
Until clinical trials become available for older men, it behooves us to follow the example of the younger study cohorts and monitor our own levels while undertaking a program of cold therapy and exercise recovery.
Testosterone in women
Sex similarities & differences
Few people realize that testosterone is the dominant sex hormone in women, just as it is in men. Lab reports comparing testosterone and estrogen are typically confusing, because these hormones are reported in different chemical units. Estrogen concentration is reported as picograms per milliliter (pg/mL) and testosterone is reported as nanograms per deciliter (ng/dL). As a consequence, to compare testosterone and estrogen measurements in identical units, you have to multiple the testosterone numbers by ten. Only then does it become obvious that healthy women have 2x-3x more testosterone circulating in their bloodstream than estrogen -- despite the fact that healthy women still have only one tenth the testosterone of healthy men.
In men, testosterone is produced in the testes. In women, it is produced in the ovaries.
Because the testes function better when slightly cooler than core body temperature, they're held outside the man's body. For example, animal studies in bulls, monkeys, and rats have shown that warming the testes inhibits testosterone and sperm production.
However, in women the ovaries are held inside the body, where they are less susceptible to cooling in an ice bath. Thus, we cannot conclude that studies of cold therapy in men are applicable to women.
Nonetheless in both sexes, testosterone has similar health effects. It builds healthy muscles, helps maintain lean body composition, and boosts libido. In fact, the most common indication for testosterone therapy in women is low sex drive (Shufelt & Brownstein 2009).
Measurement of testosterone in women is more complex than in men, because the function of the ovaries varies according to the menstrual cycle. Testosterone levels typically peak just before ovulation, and drop off during mensuration, although differences have been observed in obese women (e.g., Wajchenberg et al. 1989).
The association of maximum testosterone production with ovulation may explain why many women experience a 50% testosterone drop after menopause. Several deleterious effects can be associated with reduced testosterone in women, including "diminished sense of well-being, depression, decreased energy, decreased muscle mass and strength, decreased sexual desire, (decreased) sexual receptivity, (decreased) sexual arousal and orgasm, loss of pubic hair, changes in cognition and memory," and increased risk of bone density loss -- i.e., osteoporosis (Al-Azzawi & Palacious 2009).
Lack of research & guidance
Given the adverse health outcomes, and the inevitability of menopause, you might think that there has been considerable research attention directed towards testosterone therapies for women. But just the opposite is true.
There are still no US FDA-approved treatments for testosterone insufficiency in women, meaning that for women who do seek testosterone therapy "clinicians have no choice but to prescribe testosterone off-label, using products approved for men but at a much lower dose appropriate for women" (Traish & Morgantaler 2022). Nonetheless, adjusting dosage is problematic, given difficulties in establishing healthy target levels of testosterone in the absence of research guidance.
Cold stimulation of testosterone in women
There is one study of cold exposure and testosterone in women, and the results are promising. A few years ago, researchers recruited 32 undergraduate women to participate in a cold pressor test of pain tolerance.
The cold pressor test is a standardized psychological instrument for inducing a stress response in subjects. It requires submerging the non-dominant hand in a bowl of ice water for no more than five minutes. Most people can't last more than one minute.
The researchers never actually intended to study the relationship between cold exposure and testosterone, or they might have chosen whole-body cold water immersion, instead of the cold pressor test. But they were studying the relationship between testosterone and pain tolerance, and they chose the cold pressor test as a standardized instrument for creating pain. Because they measured saliva testosterone prior to and after the test, they created the first study of non-pharmaceutical testosterone therapy in women, even if they didn't mean to.
They discovered that cold stimulation increases testosterone in women, even without exercise (Archey et al. 2019).
Women who expressed their pain experienced a greater increase than women who did not, but both groups showed a marked increase in testosterone levels. Because the results were in young women (not menopausal) and involved submersion of one hand only, they aren't generalizable to whole body cold water immersion for older ladies.
Nonetheless, the researchers also enrolled men in their study, as a point of comparison in pain tolerance. While they did not discover that differences in pain tolerance between the sexes that could be explained by testosterone, they did discover that cold stimulation (if not full-on cold exposure) can stimulate testosterone production in young women.
Women experienced almost twice the testosterone boost that men did.
While the researchers didn't mention the potential implications of their findings as a natural therapy for producing endogenous testosterone in menopausal women, their study points to the next obvious step: measure before/after testosterone levels in women starting whole body cold water therapy in the ice bath.
If you're one of those women, send me your labs, and I will expand this study of testosterone effects so that it includes you, too!
About the Author
Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience.