You can wear underwear in a sauna, and for many men it's the practical choice. What matters is fabric: synthetics trap heat and moisture, while breathable natural-fiber underwear lets the sauna do its job without creating a hot, damp pocket where you least want one.
Most gyms and public saunas permit underwear, and plenty of private sauna users prefer it. The real question isn't whether you can wear it. It's whether what you're wearing is making things worse down where it matters.
What happens to fabric in a sauna
A traditional sauna runs between 80 and 100 degrees Celsius. At that heat, fabric behavior changes fast. Synthetics like polyester and nylon hold moisture against the skin and can trap heat in a tight band around the body. Heavy cotton gets saturated and stays wet, which creates its own problem: a warm, damp environment pressed against the area that benefits most from airflow. [1]
Natural and naturally derived fibers handle the heat differently. They wick moisture away from the skin and release it more readily, which keeps the surface drier and cooler relative to what's around it. [2]
The one area where fabric choice is not trivial
Whole-body heat from a sauna is generally considered beneficial. The area that needs to stay cooler than the rest is a different story. Research on sauna exposure and male reproductive health has found that repeated sessions can raise temperature in that region and affect spermatogenesis, the process by which sperm are produced. [3] That doesn't mean skip the sauna. It means the underwear you bring in shouldn't add to the problem.
What to wear, what to skip
| Fabric | In a sauna |
|---|---|
| Polyester / nylon | Traps heat and moisture, stays wet against skin |
| Heavy cotton | Absorbs sweat and holds it, slow to release |
| MicroModal / Lyocell (TENCEL) | Breathes well, wicks moisture, dries faster |
A relaxed fit matters too. Compression-style underwear holds fabric tight against the skin regardless of material, which limits airflow. A slightly looser cut lets air move and reduces the contact surface that traps heat.
Oakman launches Fall 2026. Founding members get first access and founding pricing locked in. Reserve your spot.
Where Oakman fits
Oakman is built specifically for active men looking for scrotal cooling all day and want the option of a cold pack for cooling in the sauna or after heat exposure. The fabric is TENCEL MicroModal, naturally derived from wood pulp rather than plastic, blended with ROICA V550, a clean Japanese stretch fiber, rather than conventional spandex. The fit is athletic with a gusset, an extra panel that gives the testicles room and airflow. Dyes are bluesign approved, so what touches your skin is controlled all the way through the supply chain.
If you're going to wear underwear in the sauna, the fabric and fit should work with the heat, not against it. Oakman is built for exactly that context. Launching Fall 2026, with the Founding 100 getting first access.
Related reading
Related reading
- Best Breathable Underwear For Men
- Best Cooling Underwear For Men
- Best Fabric For Mens Underwear In Summer
Frequently asked questions
Is it okay to wear underwear in a sauna?
Yes, most saunas allow it and many men prefer it for comfort or hygiene reasons. The main consideration is fabric: synthetics and heavy cotton trap heat and moisture, while breathable natural-fiber underwear performs better in high heat.
Does scrotal temperature affect sperm quality?
Research shows that elevated temperature in the genital area is linked to reduced sperm production. Studies on repeated sauna exposure found measurable effects on spermatogenesis, which is why keeping that area cooler than the rest of the body matters. [3]
What kind of underwear is best for sauna use?
Look for naturally derived fibers like MicroModal or Lyocell, which handle moisture and heat better than polyester or nylon. A relaxed, non-compressive fit also helps by allowing airflow rather than holding fabric tight against the skin.
Does underwear fabric affect how hot things get down there?
It can. Tight synthetic underwear creates a warm, moisture-retaining environment in the genital area. Breathable, looser-fitting natural-fiber underwear reduces that effect by allowing more airflow and faster moisture release. [1]
This article is for general educational purposes and is not medical advice. If you have specific concerns about fertility or your health, talk to a qualified clinician.
References
- Comfort related woven fabric transmission properties made of cotton and nylon. 2021. Fashion and Textiles (Springer). [Link]
- Comparative Assessment of Sensory Comfort Properties Across Eco-Friendly Textile Materials for Apparel. 2025. Journal of Natural Fibers (Taylor & Francis). [Link]
- Garolla A, et al.. (2013). Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction. [Link]
