What to Wear in the Sauna (And Why It Matters More Than You Think)

By Andrew Havill, Co-Founder of QUOR™

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The underwear industry has spent decades optimizing for "performance." Moisture-wicking polyester. Four-way stretch nylon. Compression-fit spandex. Every major brand is engineering underwear to move with you, dry faster, and feel like a second skin. And from a pure athletic performance standpoint, they've done a great job. But from a health standpoint, they've absolutely wreaked havoc on men's health and more specifically, fertility. These synthetic fabrics are made from plastic. And every day, millions of men are pressing plastic directly against the most temperature-sensitive, reproductively critical part of their body for 16+ hours straight, then walking into a 200°F sauna in the same gear without a second thought.

If you read our last article on how heat exposure affects male fertility, you already know that scrotal temperature is tightly linked to sperm health. What you wear in the sauna matters. But here's what most guys miss: what you wear the rest of the day matters just as much. And beyond what you wear, what you're doing to actively cool the groin during a sauna session might be the single most important thing you're not doing.

The Synthetic Problem Is Worse Than You Think

Polyester, nylon, and spandex have no place against your skin. Not in the sauna. Not at the gym. Not at your desk. Not in bed. These materials are derived from petroleum-based plastics, and they come with a list of problems that the underwear industry conveniently ignores.

They trap heat against your body instead of letting it dissipate naturally. They create a micro-insulation layer that blocks your skin's ability to cool itself through sweat evaporation. They shed microplastic fibers with every wear and every wash, and that shedding accelerates dramatically with heat, moisture, and friction. And they press endocrine-disrupting chemicals directly against the most absorbent, sensitive skin on your body.

This isn't just a sauna problem. The average man wears underwear for 14 to 16 hours a day. If those are synthetic boxer briefs, that's 14 to 16 hours of trapped heat, restricted airflow, and microplastic fibers against your groin. Day after day. Month after month. Year after year.

A 2018 Harvard study published in Human Reproduction studied 656 men and found that those who wore loose-fitting boxers had 25% higher sperm concentration and 17% higher total sperm count compared to men who wore tighter synthetic styles. The men in tight underwear also had higher FSH levels, a hormone marker that indicates the body is working overtime to compensate for testicular stress. Your underwear choice isn't a comfort preference. It's a health decision you're making every single day.

Now take those same synthetic fabrics and walk into a 200°F sauna. Heat accelerates every one of these problems. More microplastic shedding. More heat trapped against the groin. More chemical leaching from the fabric. You're turning an already bad situation into a worst-case scenario for your reproductive health.

The answer isn't to find better synthetics. The answer is to stop wearing them entirely, especially against the parts of your body that matter most.

Why Cooling Your Groin in the Sauna Changes Everything

Here's the part that almost nobody talks about, and it might be the most important thing in this entire article.

The whole point of the sauna is heat exposure. You want the cardiovascular benefits, the heat shock protein activation, the deep sweat, the mental clarity. The research on sauna use and longevity is compelling. A landmark study in JAMA Internal Medicine found that men who used the sauna 4 to 7 times per week had significantly lower risk of fatal cardiovascular events and all-cause mortality. You don't want to stop saunaing. The benefits are too significant.

But your testes weren't designed to handle those temperatures. Healthy sperm production requires scrotal temperatures roughly 4 to 8°F below core body temperature. That's why the testes sit outside the body in the first place. When you expose them to 185°F sauna air with no protection, scrotal temperature spikes within minutes. The 2013 Foresta study showed a 5°F increase in scrotal temperature within just 10 minutes of entering the sauna, with significant declines in sperm count, motility, DNA integrity, and mitochondrial function after regular exposure.

So the question becomes: how do you get the full-body benefits of the sauna while keeping your reproductive system protected?

The answer is targeted cooling. Specifically, icing the groin area during your sauna session.

The data on this is striking. Bryan Johnson, the longevity researcher who tracks virtually every biomarker in his body, tested this exact approach. He compared his sperm markers during sauna sessions without ice protection versus 27 consecutive daily sauna sessions with an ice pack on his groin. Without ice, his results were devastating: 54% drop in total motile count, 57% drop in motility, and 55% drop in normal morphology. With ice protection during the same sauna protocol, every marker flipped in the other direction: total motile count increased 57%, concentration increased 26%, motility increased 16%, and morphology improved 15%, all above his pre-sauna baseline. Same sauna. Same heat. Completely opposite outcomes based on one variable: whether he was cooling the groin during the session.

The concept is straightforward. If heat is the problem, localized cold is the solution. You don't have to cool your entire body. You just have to keep the groin in a safe thermal range while the rest of your body absorbs the heat.

This is the unlock that most sauna enthusiasts have never considered. You can have it both ways. Full heat exposure for your cardiovascular system, muscles, and nervous system. Targeted cold protection for your reproductive system. The two aren't mutually exclusive if you have the right setup.

The Problem With DIY Cooling Solutions

Once guys learn about scrotal cooling in the sauna, the first instinct is to improvise. Grab a cold towel. Hold a generic ice pack in your lap. Sit on something cold. And while the instinct is right, the execution falls apart almost immediately.

A cold towel warms up within 2 to 3 minutes in a 200°F sauna. It provides almost no sustained cooling and you're constantly re-soaking and wringing it out. That's not a sauna session. That's a chore.

A generic ice pack on your lap doesn't stay in place. You're holding it there with your hands, adjusting it every time you shift position, and it's sliding around on sweaty skin. It's awkward, it's distracting, and it pulls you completely out of the meditative, recovery-focused mindset that makes the sauna valuable in the first place.

A bag of ice melts fast, leaks water everywhere, and creates a mess on the sauna bench. Not exactly the premium wellness experience you're going for.

Going nude does nothing to protect from heat. Your testes are fully exposed to the same extreme air temperature as the rest of your body. Nudity might be fine for thermoregulation in general, but it offers zero targeted cooling where you need it most.

Regular cotton boxers are better than synthetics for everyday wear, but they're still completely passive in the sauna. They don't cool anything. They're just fabric sitting between your skin and 200°F air. Better than plastic? Yes. Actually solving the problem? No.

Every one of these "solutions" fails for the same reason: none of them were designed for targeted scrotal cooling during a sauna session. They're all improvised workarounds that require you to actively manage them instead of actually enjoying your sauna.

QUOR: The Only Purpose-Built Solution

This is exactly why QUOR exists. We didn't set out to make another underwear brand. We set out to solve a specific problem: how does a man who saunas regularly protect his reproductive health without giving up the practice that benefits every other system in his body?

The answer required three things working together.

First, premium materials all day. The body of the QUOR boxer is 95% bamboo and 5% elastane. Bamboo is naturally antimicrobial, moisture-wicking, thermoregulating, and incredibly soft. No polyester. No nylon. Whether you're at work, at the gym, or heading into the sauna, you're wearing a material that breathes and regulates temperature instead of trapping heat against your body.

Second, 100% cotton where it counts. The groin area of every QUOR boxer is a dual-layer pouch made from 100% cotton. Zero synthetics touching the most sensitive, temperature-critical part of your body. No microplastic shedding. No chemical leaching. No trapped heat from plastic fabrics. Just clean, breathable cotton against your skin, all day long.

Third, and this is the game-changer: a custom cooling insert that actually stays in place. Every pair of QUOR boxers comes with a BPA-free, non-toxic cooling insert specifically shaped to fit inside the dual-layer cotton pouch. You cool it down before your session, slide it into the pouch, and it stays exactly where it needs to be for the duration of your sauna. No holding anything with your hands. No adjusting. No sliding around. No melting ice bags. Just targeted, hands-free thermal defense for your groin while the rest of your body gets the full benefit of the heat.

This is the piece that doesn't exist anywhere else. There is no other boxer on the market with an integrated pouch designed to hold a custom cooling insert during sauna use. Not from the big athletic brands. Not from the "premium" underwear companies. Nobody has built this because nobody was thinking about the problem from this angle.

QUOR is one product that solves the full equation. Clean materials you can wear all day. Zero synthetics against the groin. And targeted cooling that works hands-free in the sauna. All day. Every session. No compromise.

Practical Tips for Your Sauna Routine

Beyond what you wear, here are a few additional principles that protect your body in the heat:

Cool down after. A cold plunge or cold shower post-sauna helps bring your entire body temperature back to baseline faster. If you're already doing contrast therapy, you're ahead of the game. The cooling insert protects you during the session. The cold plunge finishes the job after.

Keep it clean. Shower before you enter. Sit on a towel. Don't wear what you worked out in without changing first. Basic hygiene that protects you and everyone sharing the space.

Consider a sauna hat. Wool or felt sauna hats insulate your head from the most intense heat at the top of the sauna (hot air rises, and the temperature difference between bench level and ceiling is significant). They help you stay comfortable longer and extend your sessions safely. We include one in the QUOR lineup for exactly this reason.

Skip the metal. Jewelry, watches, piercings... anything metal heats up fast in a sauna and can burn your skin. Leave it in the locker.

Think long-term. A single sauna session isn't going to wreck your fertility. But the compounding effect of daily synthetic underwear plus regular sauna use plus prolonged sitting plus other heat sources adds up over months and years. Small, smart choices compound in your favor. Ditch the synthetics. Ice the goods. Protect your future.

The Bottom Line

What you wear in the sauna isn't just about modesty or etiquette. It's a health decision. And what you're doing to actively protect your groin from heat during your session is just as important as what fabric you're wearing.

Now you know there's a better way. Ditch the synthetics entirely. Wear clean, natural materials against your skin all day. And when you step into the sauna, make sure you have targeted cooling in place, hands-free, right where it matters most.

That's not a hack. That's not a workaround. That's QUOR.

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Sources:

• Laukkanen, T., et al. (2015). Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events. JAMA Internal Medicine, 175(4), 542–548.
• Garolla, A., et al. (2013). Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction, 28(4), 877–885.
• Minguez-Alarcon, L., et al. (2018). Type of underwear worn and markers of testicular function among men attending a fertility center. Human Reproduction, 33(9), 1749–1756.
• Jung, A., et al. (2005). Genital heat stress in men of an infertile couple. International Journal of Andrology, 28(Suppl 1), 37.
• Napper, I.E. & Thompson, R.C. (2016). Release of synthetic microplastic plastic fibres from domestic washing machines. Marine Pollution Bulletin, 112(1-2), 39–45.

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Andrew Havill is the co-founder of QUOR™, a men's vitality brand built around thermal defense. He saunas almost every day and built QUOR because the product he needed didn't exist. Learn more at quorwellness.com.