Sauna-level heat genuinely affects the testicles. It slows sperm production, and at the cellular level it slows testosterone production too. Both effects are established, and both are reversible. A whole-body sauna is still one of the best things a man can do for his health, so the move isn't to skip it. It's to keep the testicles cool while the rest of you gets hot.
The popular version of this, "heat kills sperm, avoid the sauna," is half right and points you at the wrong fix. Heat does matter for the testicles, more than most men realize. But quitting the sauna throws away real health benefits, and it ignores the heat that actually does the most damage: the close, constant kind you sit in every day. Here is the honest picture, and the fix that keeps both the sauna and the testicles.
Heat is real for the testicles, not a myth
Your testicles are built to run a few degrees cooler than the rest of you, which is why they sit outside the body. Warm them up and two things happen at once: the cells that build sperm slow down, and sperm quality takes a hit.
This is measured, not guessed. In a 2013 study, Garolla and colleagues had ten healthy men sit in a hot sauna twice a week for three months. Sperm count and motility dropped sharply, then recovered fully about six months after they stopped. [1] Shefi and colleagues, in 2007, found the same with wet heat: men who simply gave up their regular hot tubs saw their moving sperm climb back up, in some cases several times over. [2] So the accurate summary of heat and sperm is a real, reversible slowdown. Reversible does not mean harmless. It means the testicles respond when you change the conditions, in both directions.
What heat does to testosterone
Deep in the testicles sit the Leydig cells, and they make roughly ninety five percent of a man's testosterone. Heat gets in their way. In the lab, when you heat these cells, the enzymes they use to build testosterone slow down, and the cholesterol they would normally turn into testosterone backs up, unused. That has been measured at the cellular level in animal and cell studies. [3][4] It is not in question.
What has not been run yet is the long trial: whether that daily heat drags a healthy man's circulating testosterone down over a lifetime. There is a clear mechanism to think it could, and that study should be done. Until it is, the honest line is that heat slows the machinery in the moment, which is established, while the lifetime effect on blood testosterone is a fair question no one has answered. The confident claims in both directions, that a sauna crashes your testosterone or that it lifts it, are running ahead of the evidence.
The sauna itself is still worth it
None of that is a reason to give up the sauna, because a whole-body sauna is one of the best things a man can do for his health. Finnish researchers followed more than two thousand men for two decades and found that the ones using a sauna four to seven times a week were about forty percent less likely to die of any cause over those years, with their risk of dying from heart disease cut roughly in half, compared to men who went once a week. [5] Add better sleep, lower cortisol, and a repair response that builds a healthier body overall. The sauna is a genuine health lever. The catch is that it heats your whole body, including the one place built to stay cool.
The heat that does the most damage is the everyday kind
Here is the part the "avoid the sauna" advice misses. The occasional sauna is brief and gets a chance to cool off afterward. The heat that never cools off is the close, constant kind aimed right at the testicles all day: tight synthetic underwear that traps warmth, a laptop on the lap, which can raise testicular temperature a couple of degrees within an hour, [6] and long uninterrupted stretches of sitting. That is a far longer daily heat exposure than a sauna, and it is the one most men never think about. Hot tubs belong in the same bucket, wet heat held on the testicles, and are worth skipping while you are actively trying to conceive.
How to keep the sauna and keep the testicles cool
The two goals are not in conflict, because cooling the testicles is a physical problem with a physical fix, and the fix belongs during the heat, not after it. Active cooling only helps while the testicles are actually warm; a cold shower afterward feels good but does nothing to undo the exposure that already happened. That is the whole idea behind Oakman: a slim removable cold pack that keeps the testicles cool during the sauna itself, and breathable, airflow-first boxer briefs that keep them cooler across the rest of the day. It makes no claim on your sperm or your hormones. It keeps the area cooler, which is simply the temperature the testicles are built to work at. This holds even if fertility is not your concern, since the same heat also slows testosterone production at the cellular level, and many men use a cold pack in the sauna for that reason alone. Pair that with getting the laptop onto a desk, breaking up long sitting, and trading tight synthetic underwear for a breathable fit, and you have handled the everyday heat too.
If you're actively trying to conceive
Sperm takes roughly two to three months to build, so the conditions in your body today show up in a semen analysis months from now, and any heat you ease off reverses on that same kind of timeline. If you are trying to conceive or already have a low count, get a semen analysis so you are working from data, keep the testicles cool day to day, skip the hot tub for now, and use a cold pack if you want to keep saunaing. Talk to a doctor before making big changes either way.
The bottom line
Heat is not the fertility boogeyman that says avoid the sauna, and it is not a non-issue you can ignore. It genuinely warms the testicles, which slows both sperm and testosterone production, and both recover when the heat eases. The smart play keeps the sauna, with its real, proven health benefits, and keeps the testicles cool at the same time: a cold pack in the heat, breathable underwear all day, and a little attention to the everyday heat that does more damage than any Saturday sauna ever will.
Frequently asked questions
does sauna use hurt sperm count
Yes, temporarily, and it recovers. Garolla and colleagues (2013) had ten healthy men sauna twice a week for three months; sperm count and motility dropped sharply, then recovered fully about six months after they stopped. Shefi and colleagues (2007) found men who gave up regular hot tubs saw their moving sperm climb back up. Heat causes a real, reversible slowdown in sperm production, because the testicles are built to run a few degrees cooler than the rest of the body.
does a sauna lower testosterone in men
At the cellular level, yes. Heat slows the enzymes the Leydig cells use to build testosterone, and that has been measured in animal and cell studies. What has not been tested is whether that daily heat drags a healthy man's circulating testosterone down over a lifetime. There is a plausible mechanism to think it could, and that study should be done, but it has not been run yet. Claims that a sauna crashes your testosterone, or that it raises it, both run ahead of the evidence.
if heat affects the testicles, should i stop using the sauna
No. A whole-body sauna is one of the best things a man can do for his health. Finnish research following more than two thousand men for two decades found frequent sauna users were about forty percent less likely to die of any cause, with heart-disease death cut roughly in half, plus better sleep and lower cortisol. The goal isn't to quit the sauna, it's to keep the one place that needs to stay cool from overheating while you enjoy the rest of the benefits.
how do you keep the testicles cool during a sauna
Cool them during the session, not after, because active cooling only helps while the testicles are actually warm and a post-session cold shower doesn't undo the exposure. A slim removable cold pack held against the testicles during the sauna keeps them cool while the rest of you heats up, and breathable, airflow-first underwear keeps them cooler the rest of the day, which is when the close, constant heat from tight synthetic fabric, a laptop, and long sitting really adds up.
This content is for educational purposes only and is not medical advice. Oakman products are designed for physical comfort and cooling; they make no claims about fertility, sperm quality, or hormone levels. Consult a healthcare professional for personalized advice.
References
- Garolla A, et al. (2013). Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction. [Link]
- Shefi S, et al. (2007). Wet heat exposure: a potentially reversible cause of low semen quality in infertile men. International Brazilian Journal of Urology. [Link]
- Durairajanayagam D, Agarwal A, Ong C. (2015). Causes, effects and molecular mechanisms of testicular heat stress. Reproductive BioMedicine Online. [Link]
- Cai H, Qin D, Peng S. (2021). Responses and coping methods of different testicular cell types to heat stress: overview and perspectives. Bioscience Reports. [Link]
- Laukkanen T, et al. (2015). Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine. [Link]
- Sheynkin Y, et al. (2005). Increase in scrotal temperature in laptop computer users. Human Reproduction. [Link]