One of the most searched questions about sauna use: does it affect testosterone? The short answer is nuanced — and worth understanding correctly, because the actual mechanism is more interesting than most articles describe.
Heat Stress and Testosterone: The Basic Biology
The testes operate best at slightly below core body temperature — which is why they're housed outside the body. Prolonged, direct scrotal heating is known to temporarily reduce sperm production and can affect testosterone production in extreme cases (think: very hot baths held for extended periods, or occupational heat exposure). This is the origin of the concern about sauna and testosterone.
However, sauna and cold plunge protocols don't expose the testes to sustained extreme heat the way occupational heat does. Typical sauna sessions — 20–30 minutes at 130–150°F in an infrared sauna — raise core temperature moderately, with scrotal temperature affected only briefly. The question is whether this brief thermal stress has meaningful effects on testosterone, positively or negatively.
What the Research Shows
Short-Term: Acute Testosterone Response
Sauna use produces acute physical stress similar to moderate exercise. The body responds to this stress partly through transient hormonal activation — including a brief rise in luteinizing hormone (LH), which stimulates testosterone production. Several studies document a short-term testosterone increase in the hours following a sauna session, similar in mechanism to the post-exercise testosterone spike.
Long-Term: Growth Hormone Is the Bigger Story
The more robust hormonal effect of regular sauna use is on growth hormone (GH), not testosterone. A study published in Acta Physiologica found that two 20-minute sauna sessions separated by a 30-minute cooling period produced up to a 16-fold increase in growth hormone. GH is central to muscle repair, fat metabolism, and cellular regeneration — arguably more relevant to the performance and longevity outcomes most sauna users are pursuing.
Cold Exposure and Testosterone
Cold water immersion is where the testosterone research is more direct. Multiple studies document that cold exposure — particularly cold plunge — produces a significant, rapid rise in norepinephrine (200–300% in some studies) and a consistent acute rise in testosterone. The Wim Hof method studies showed measurable hormonal effects from cold protocols. The combination of regular cold exposure and sauna use together appears more favorable for hormonal health than either alone.
Red Light Therapy: The Emerging Testosterone Story
The most interesting emerging research on biohacking tools and testosterone involves red light therapy — specifically, photobiomodulation applied near the testes. A 2013 study found that men receiving low-level laser therapy to the scrotal area showed significantly higher testosterone levels than controls. Follow-up research has been limited but the mechanism (mitochondrial stimulation in Leydig cells, which produce testosterone) is biologically plausible. This is early-stage research, but it's worth following as the evidence develops.
The Practical Picture
For men focused on hormonal health after 40:
- Regular sauna use (4+ sessions per week) supports overall health markers associated with healthy testosterone levels — better sleep, lower inflammation, reduced cardiovascular stress — even if direct testosterone effects are modest
- Cold plunge has more direct evidence for acute testosterone and norepinephrine elevation
- Growth hormone response to sauna is substantial and well-documented — this is likely the primary hormonal benefit
- If testosterone is a primary concern, work with a physician to measure baseline levels and identify root causes before relying solely on lifestyle interventions
What Actually Drives Testosterone Long-Term
Sleep quality, body composition, stress levels, and resistance training have larger and more consistent effects on testosterone than any single biohacking tool. The sauna and cold plunge contribute by improving sleep (sauna), reducing chronic stress (both), and supporting recovery from resistance training (both) — which creates the conditions for healthy hormone production rather than directly driving it.
The Bottom Line
Sauna use at typical session lengths and temperatures does not suppress testosterone and likely produces modest short-term increases. The growth hormone response is more substantial and better documented. Cold plunge has more direct evidence for testosterone elevation. Together, these tools support the underlying conditions — sleep, recovery, stress reduction — that allow healthy hormonal function. They're part of the system, not a substitute for addressing root causes.