Does Sauna Increase Testosterone? What the Evidence Actually Shows

Originally published 2025 · Updated April 2026 with new research including the 2025 Canadian Urological Association Journal review of alternative men's health interventions

Few claims in the men''s health space are repeated as confidently as "sauna raises testosterone." It appears in fitness content, biohacking communities, and supplement marketing as established fact. The evidence behind it is considerably more complicated — and considerably more honest when told accurately.

The short answer is no — sauna does not directly and meaningfully raise testosterone. The longer answer is that sauna does several things that indirectly support a healthier hormonal environment, and those effects are worth understanding properly.

TL;DR

• Repeated Finnish sauna use induces a significant decrease in cortisol but does not cause significant changes in testosterone, DHEA-S, or prolactin levels.
• Multiple studies report no differences in reproductive hormones — FSH, LH, testosterone, estradiol, inhibin B, or sex hormone-binding globulin — after sauna exposure.
• A 2025 review in the Canadian Urological Association Journal found mixed outcomes with some temporary testosterone increases, but concluded the overall evidence for testosterone enhancement is inconsistent and limited by small sample sizes.
• The indirect case is more robust: sauna significantly reduces cortisol — testosterone''s primary hormonal antagonist — and improves deep sleep, the main context for testosterone production.
• The fertility caution is real: repeated sauna use temporarily reduces sperm count and motility, with effects reversing within roughly six months of stopping.

What the Direct Evidence Shows

The most frequently cited research on sauna and testosterone involves a study measuring endocrine responses to repeated Finnish sauna sessions in young adult men.

Testosterone increased from 4.04 to 4.24 ng/ml — a non-significant change. Serum cortisol levels decreased significantly from 13.61 to 9.67 µg/ml across 72 minutes of sauna treatment. The conclusion: repeated use of Finnish sauna induces a significant decrease in cortisol concentrations but does not cause significant changes in testosterone, DHEA-S, or prolactin levels.

This finding is consistent across the literature. No differences in relevant reproductive hormone levels — FSH, LH, testosterone, estradiol, inhibin B, sex hormone-binding globulin — appear after sauna exposure in multiple studies.

A comprehensive 2025 review published in the Canadian Urological Association Journal assessed alternative therapies in men''s health, including sauna, cold water immersion, light therapy, and nutritional supplements. On sauna specifically, the review found mixed outcomes with some temporary increases in testosterone and reversible adverse effects on sperm parameters. The overall conclusion was that sauna and many other popular interventions lack concrete evidence for testosterone enhancement, with studies suffering from small sample sizes, poor blinding, and reliance on surrogate endpoints.

The direct evidence is clear: sauna does not produce a clinically meaningful or sustained increase in testosterone. The marketed claim is not supported by current research.

The Indirect Case: Why It''s More Interesting

This is where the honest and more nuanced story lies — and it is genuinely worth understanding.

Cortisol Is Testosterone''s Primary Antagonist

Cortisol and testosterone operate in opposition. Chronically elevated cortisol — from sustained work stress, training overload, poor sleep, or metabolic dysfunction — is one of the most consistent and well-documented suppressors of testosterone in healthy men. The mechanism operates through the HPA axis: sustained cortisol elevation downregulates the production of luteinising hormone (LH), the primary upstream signal for testicular testosterone production.

Sauna''s documented effect on cortisol is significant — a reduction from 13.61 to 9.67 µg/ml across 72 minutes, with a greater decrease observed in men with higher baseline cortisol. For men with chronically elevated cortisol from training stress, occupational stress, or sleep deprivation, this cortisol-reducing mechanism is the most meaningful way sauna use supports their testosterone — not through direct stimulation but through removal of the primary suppressor.

The distinction between directly raising testosterone and removing what suppresses it is meaningful. The more evidence-supported claim is that regular sauna use supports healthy testosterone by reducing the primary suppressors: chronic cortisol elevation, poor sleep quality, chronic inflammation, and metabolic dysfunction.

Sleep Is Where Testosterone Is Made

The majority of daily testosterone production occurs during sleep — specifically during deep sleep stages. Sleep deprivation is one of the most powerful suppressors of testosterone in healthy men. A study published in the Journal of the American Medical Association found that one week of sleep restriction to five hours per night reduced daytime testosterone by 10 to 15% in young, healthy men.

Sauna''s documented sleep-improvement effect — through the core temperature drop mechanism that enhances deep sleep when sauna is used roughly 90 minutes before bed — is therefore directly relevant to testosterone optimisation.

The mechanism: using sauna 90 minutes before bed raises core temperature during the session. The subsequent drop in core temperature after leaving the sauna signals sleep onset to the brain, facilitating faster sleep initiation and deeper sleep stages. Better deep sleep produces more testosterone — not through sauna''s direct action on hormone production, but through the sleep quality improvement it facilitates.

For the full picture on sauna''s broader effects on sleep, cardiovascular health, and longevity, see Sauna Health Benefits: What the Science Actually Shows.

Inflammation and Metabolic Health

Chronic low-grade inflammation and poor metabolic health are both associated with lower testosterone. Sauna''s well-documented anti-inflammatory effects — suppression of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6 — and its associations with improved lipid profiles and cardiovascular markers create a broader metabolic environment more conducive to healthy testosterone production over time.

This is an indirect pathway — but it is physiologically coherent and consistent with the mechanisms through which sauna produces its broader health effects.

The Growth Hormone Response

One hormonal effect of sauna that is well supported and often underemphasised is growth hormone. Acute sauna sessions — particularly at higher temperatures — stimulate significant growth hormone release, with some studies documenting increases of several hundred percent above baseline during and immediately after a session.

Growth hormone plays a complementary role to testosterone in supporting muscle protein synthesis, body composition, and recovery. For men focused on physical performance and body composition, the growth hormone response to sauna is a more robustly documented hormonal effect than any testosterone association — and is worth including in the picture.

The Fertility Caution

This is the most clearly negative finding in the sauna and male hormonal health literature, and it warrants direct communication.

One study showed reversible reduction in sperm count and motility in healthy men after repeated sauna sessions, with all effects reverting to normal six months after cessation. Scrotal temperature is 2 to 3°C lower than body core temperature, which is considered essential for spermatogenesis. It is disturbed when testicular temperature is elevated — as occurs during sauna sessions.

The practical guidance is unambiguous: men who are actively trying to conceive should avoid regular sauna use or significantly limit it until conception has occurred. The effect is reversible — sperm parameters return to normal within approximately six months of stopping — but during active attempts at conception, the risk is not worth taking.

This caution does not apply to general health use. Men not attempting to conceive can use sauna regularly without concern about irreversible reproductive harm. It is a specific, time-limited consideration for those in active family planning.

Practical Guidance for Men

If the goal is supporting hormonal health through sauna use, the evidence-based approach focuses on the indirect pathways rather than expecting direct testosterone elevation:

• Use sauna consistently — two to four sessions per week of 15 to 20 minutes each reduces cortisol reliably and supports the cardiovascular and metabolic environment associated with healthy testosterone.
• Time sessions for sleep benefit — sauna ~90 minutes before bed exploits the core temperature drop mechanism most effectively, supporting the deep sleep that drives testosterone production.
• Combine with resistance training — testosterone concentrations are higher in men with higher baseline physical activity, both before and after sauna bathing. The combination of regular strength training and sauna use supports healthy testosterone through complementary mechanisms.
• Manage the fertility consideration — if trying to conceive, pause regular sauna use until conception has occurred.
• Do not use sauna as a substitute for addressing the primary drivers of low testosterone — sleep quality, resistance training, body composition, alcohol intake, and chronic stress management remain the primary evidence-based levers. Sauna supports these; it does not replace them.

Frequently Asked Questions

Does sauna directly increase testosterone?

No — not in a clinically meaningful or sustained way. Multiple studies have found no significant change in testosterone following Finnish sauna sessions. Some studies show minor, non-significant acute increases that do not persist. The direct evidence for sauna as a testosterone booster is not supported by current research.

How does sauna affect cortisol?

Sauna produces a significant and reliable reduction in cortisol — one of the most consistently documented endocrine effects of sauna use. A study in young adult men found cortisol decreased from 13.61 to 9.67 µg/ml across 72 minutes of sauna treatment, with greater reductions in those with higher baseline cortisol. Since cortisol and testosterone are inversely related, this cortisol reduction is the primary mechanism through which sauna indirectly supports the hormonal environment for healthy testosterone.

Does sauna affect fertility?

Yes — repeated sauna use temporarily reduces sperm count and motility due to elevated scrotal temperature during sessions. These effects are reversible, with sperm parameters returning to normal within approximately six months of stopping. Men actively trying to conceive should avoid or significantly limit sauna use until conception has occurred.

Does infrared sauna affect testosterone differently than Finnish sauna?

Most research on sauna and testosterone is based on Finnish sauna. Infrared sauna operates at lower temperatures — 50 to 65°C versus 80 to 100°C — which means scrotal temperature elevation is less pronounced. The cortisol-reducing and sleep-improving effects of infrared sauna are documented, suggesting the indirect hormonal support mechanisms apply. The direct hormonal effects at lower temperatures are less studied.

What is the best sauna protocol for men''s hormonal health?

Two to four sessions per week of 15 to 20 minutes each, timed roughly 90 minutes before bed for sleep benefit, combined with regular resistance training and adequate protein intake. The goal is supporting the indirect pathways — cortisol reduction, sleep quality, inflammation management — rather than expecting direct testosterone elevation from sauna alone.

The Bottom Line

Sauna does not directly and meaningfully raise testosterone. The claim is widespread in men''s health content and not supported by the evidence.

What sauna does do is reduce cortisol — testosterone''s primary hormonal antagonist — improve deep sleep quality, and lower systemic inflammation. Through these indirect pathways, consistent sauna use supports the physiological conditions under which healthy testosterone is most effectively maintained. That is a meaningful and honest benefit, even if it is less dramatic than the marketed version.

For a comprehensive approach to supporting healthy testosterone through sleep, training, nutrition, and stress management, the Testosterone Reset from the Reset Series™ covers the full evidence-based protocol.

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Related reading: Sauna Health Benefits: What the Science Actually Shows · Can HRT Patches Help Prostate Cancer? · What Is ''Toxic Masculinity'' — and What''s Actually Causing It?

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