Does a sauna boost testosterone?

Search for sauna benefits for men and you'll soon find the claim that heat raises testosterone. It's an appealing idea, and the studies that measured it are short and easy to check. The answer is less exciting than the claim, and there's one effect on men's health that gets mentioned far less often.

Where the claim comes from

Heat really does change hormone levels. In a sauna, levels of noradrenaline, prolactin and growth hormone can all rise, sometimes by large multiples. It's a short step from there to assume testosterone goes up too, and from there to the idea that a sauna helps you build muscle or improves your sex drive.

The growth hormone figures are a story of their own, covered in our guide to sauna and growth hormone. For testosterone, the studies are fewer, and they don't show much.

What the studies measured

Here is what the main studies found when they checked testosterone:

• Finland, 1986. Ten healthy men sat in an 80 °C (176 °F) sauna for an hour, twice a day, for seven days. Their growth hormone and prolactin rose sharply. Testosterone, and the hormones that tell the testes to make it, did not change significantly.
• Finland, 1989. Eight young men were tested in three sessions: 80 °C dry and 100 °C (212 °F) dry until they felt uncomfortable, and 80 °C made humid until they were exhausted. Testosterone rose only in the last, most punishing session.
• 2021 study of young men. 30 physically active men aged 19 to 26 did four 12-minute rounds at 90–91 °C (194–196 °F), each followed by a minute in cold water. Average testosterone went from 4.04 to 4.24 ng/ml, a change too small to rule out chance.
• 2013 fertility study. Ten men used a sauna twice a week for three months. Their sex hormones showed no significant change.

So across several studies, in different setups, testosterone barely moved. Where it did rise, it was under heat far beyond anything you'd want to do regularly, and it was only measured around the session itself. No study has shown a lasting rise in testosterone from regular sauna use.

It's also worth knowing that in the 2021 study, the men who did more physical activity had higher testosterone before and after the sauna. That's a link with activity, not with the sauna.

Cortisol, the stress hormone

One hormone does seem to respond. In the 2021 study, cortisol fell by about 29% across the session. In the 1986 Finnish study it was also lower at the end of the week, and in the 1989 study it fell at both dry temperatures.

You'll sometimes read that lower cortisol means "more room" for testosterone. That's a theory, not something these studies showed: cortisol dropped and testosterone stayed about the same. A calmer evening is a fine reason to sit in a sauna. Hormonal gains aren't.

Heat and sperm

The testes sit outside the body for a reason. Sperm develop best a few degrees below core body temperature, usually quoted as 2–4 °C cooler, and reviews of the research describe even mild warming as harmful to sperm production.

A 2013 study in the journal Human Reproduction tested what regular sauna use does. Ten men with normal sperm used a Finnish sauna at 80–90 °C (176–194 °F) for 15 minutes, twice a week, for three months. The researchers measured their sperm before, at the end, and three and six months after they stopped.

• At the end of the three months, sperm count and motility (how well sperm swim) were strongly impaired.
• The sperm also showed changes in how their DNA was packed and in how well their mitochondria, the cell's power supply, worked.
• Testosterone and the other sex hormones didn't change.
• Six months after stopping, everything was back to normal.

Ten men is a small study, and they all had normal sperm to begin with, which the authors named as the main limitation. An older review from 2001 had concluded that sauna bathing doesn't affect fertility. But the 2013 study measured sperm directly, and the result fits with what's known about heat and the testes.

If you are trying for a baby

In the study the effect was fully reversible, which is reassuring. But if you and your partner are trying to conceive, it's sensible to:

• cut down on saunas for a few months, and go easy on hot tubs too, since the problem is heat
• keep rounds short if you do go, and cool down properly between them
• mention your sauna habit if you see a fertility doctor or have a semen test

In the 2013 study, recovery took up to six months, so give it time.

If you think your testosterone is low

Low testosterone is diagnosed with blood tests, and it can have causes that need a doctor's attention. If you're worried, see your doctor rather than buying a sauna. What the research on sauna supports is more modest: it's relaxing, it's linked to better heart health in long-term Finnish studies, and many people like how it feels after training. See sauna benefits and sauna before or after a workout for more.

Who should be careful

Check with a doctor first if you have a heart condition, unstable or very high blood pressure, or take medicine that affects blood pressure or sweating. Men trying for a baby should think about the effect on sperm. Never use a sauna after drinking alcohol, don't try to copy hour-long research protocols, and leave if you feel dizzy, sick or confused. Our guide to how long to stay in a sauna has sensible times.

This guide is general information, not medical advice.

Where to find a sauna

Find My Sauna lists 2,616 places with a Finnish-style sauna. These cities have the most:

Raua Saun

Tallinn · Finnish and steam sauna

Vizlas pirts

Riga · Banya

Anne Saun

Tartu · Finnish sauna

Frequently asked questions