Fertilitywear™ vs. Traditional Underwear: What You Need To Know

Written By The Mr. Fertyl Research & Education Team

Men’s fertility can be affected by factors we might overlook, including our underwear. Studies suggest sperm counts and quality have been declining globally [1]. Many experts note that the testicles need to stay a few degrees cooler than core body temperature (around 94°F vs 98.6°F) to make healthy sperm [5]. Traditional tight or synthetic underwear can trap heat and moisture, potentially raising scrotal temperature. This is important because elevated scrotal heat is known to harm testicular function [2]. Even a moderate temperature rise is thought to impair sperm production over time.

But heat isn’t the only concern. Everyday clothing may contain chemicals like phthalates and BPA – endocrine disruptors tied to lower sperm counts and motility [7][11]. Phthalates are often used in activewear and printed fabrics, and higher phthalate exposure in men has been linked to significantly poorer sperm quality [8][11]. Similarly, certain flame-retardant and stain-resistant coatings in textiles can disrupt hormones. Tight, non-breathable fabrics also trap moisture, which can lead to chafing or fungal infections [6]. In short, conventional underwear can create a warm, wet environment that is less than ideal for fertility.

Traditional Underwear: What to Watch Out For

Underwear style and fabric really matter. Some key issues with many standard undergarments:

  • Raised Temperature: Tight briefs or snug synthetic blends press the testes against the body and hold in heat. Sperm production drops when testicular temperature rises. For example, one fertility study found that men who habitually wore loose-fitting boxers had higher sperm counts than those in tight underwear [2]. (Note: some doctors caution that the evidence on briefs vs. boxers is mixed [3], but it’s clear that staying cool helps sperm.)
  • Chemical Exposure: Many fabrics and dyes contain endocrine-disrupting chemicals (phthalates, bisphenol A, etc.). Research shows that men with higher phthalate levels tend to have significantly lower sperm counts and poorer sperm quality [7][11]. An EarthDay report highlights that phthalates are used in fabric printing and performance wear, and are known endocrine disruptors [8]. By contrast, natural fibers like Bamboo Lyocell contain no added phthalates or BPA.
  • Moisture & Friction: Materials that don’t breathe well trap sweat, leading to chafing, rashes, or jock itch. In a health survey, wearing very tight pants was linked to more yeast infections and skin irritation, due to trapped warmth and moisture [6]. Over time, constant rubbing and heat can damage delicate scrotal skin. Comfortable, moisture-wicking fabrics help prevent these problems and keep everything cooler.

Some experts say that science isn’t 100% settled on underwear and fertility – a Cleveland Clinic urologist notes that current studies “probably doesn’t matter” too much [4]. Mayo Clinic advice similarly points out that scrotal temperatures are normally a few degrees below body temp and anything that chronically raises it (tight underwear, hot tubs, laptop on lap) should be avoided [3]. In practice, it makes sense for fertility-minded men to choose loose, breathable underwear as a precaution.

Flat lay of non-toxic bamboo men’s underwear in black and beige, fertility-safe and breathable.

Better Underwear. Healthier Sperm.

Make the Switch

Fertilitywear™ and Bamboo Lyocell

Enter fertilitywear: underwear designed with sperm health in mind. The idea is simple – give your testicles a cooler, cleaner environment. Mr. Fertyl’s bamboo-based underwear are one example. They feature an airy cut that allow the testes to hang naturally and not be pressed against warm skin. This design improves airflow and helps keep the scrotal area cooler than tight briefs would.

Just as important is the material. Mr. Fertyl’s underwear is made from Bamboo Lyocell, a plant-based, natural fiber. Bamboo Lyocell is extremely soft and exceptionally breathable. It wicks moisture away from the skin much better than conventional cotton, so sweat evaporates quickly [5]. Bamboo also has natural antimicrobial qualities (“bamboo kun”), which help prevent odors and skin irritation. Because Bamboo Lyocell is made in a closed-loop process, the fabric comes out free of harmful residues – no phthalates, no BPA. The material is also hypoallergenic, making it gentle on sensitive skin.

These features directly support fertility. Cooler, drier conditions mean sperm aren’t exposed to extra heat or chemicals. The Harvard fertility study mentioned above concluded that styles keeping testicles cooler (like boxers) correlated with a 25% higher sperm concentration [2] – the exact benefit fertilitywear seeks to provide. Mr. Fertyl’s underwear aim to replicate that effect: the bamboo maintains a slightly cooler baseline for testicles. And by using a clean, natural fabric, the underwear avoids adding any chemical stress to sperm or the delicate scrotal skin.

Environmental Benefits: Bamboo vs. Cotton

Fertilitywear offers another big advantage for eco-conscious men: it’s better for the planet. Conventional cotton farming is extremely water- and pesticide-intensive. The World Wildlife Fund notes that cotton crops consume vast water and chemical resources, often depleting rivers and polluting ecosystems [9]. (For example, diverting water for cotton irrigation has contributed to disasters like the drying of the Aral Sea.) Producing one cotton T-shirt is often cited as requiring thousands of liters of water [10]. In short, your average cotton undie has a significant ecological footprint.

Bamboo is very different. It grows rapidly with minimal irrigation and no need for pesticides or fertilizers [10]. Mature bamboo forests can thrive in poor soil and actually help rebuild it. Bamboo Lyocell production is also eco-friendly: it uses a non-toxic solvent in a closed-loop system that recovers over 99% of water and chemicals. (As a result, Bamboo Lyocell fabric is fully biodegradable, unlike polyester.) One sustainability report even notes that bamboo plants produce about 35% more oxygen per acre than an equivalent stand of trees [10].

In practical terms, wearing bamboo-based fertilitywear means using far fewer natural resources. It also reduces pollution from farming and manufacturing. Choosing Bamboo Lyocell instead of cotton means you’re supporting textiles that leave a smaller footprint. For sustainability-minded men, that’s a win-win: comfort and fertility support for your body, and less harm to the environment.

Flat lay of non-toxic bamboo men’s underwear in black and beige, fertility-safe and breathable.

Worried About Your Fertility? Start with Your Underwear.

Try Fertilitywear™ Now

Conclusion

In the end, fertilitywear puts reproductive health front and center in a very practical way. The science suggests that lower testicular heat and fewer chemical stressors help sperm thrive [2][11]. Mr. Fertyl’s Bamboo Lyocell underwear addresses both factors. It offers a breathable, supportive fit that helps keep the testes cooler, and it uses a natural fabric free of harmful toxins. It’s a small switch that can make your daily environment more sperm-friendly.

For a health-conscious man, fertilitywear is an easy step toward protecting fertility. It’s about reducing avoidable risks – heat, chemicals, moisture – and giving your reproductive system the best conditions possible. Plus, it aligns with eco-friendly values. By wearing bamboo-based underwear, you’re supporting sustainable practices while giving your fertility a boost. In the conversation about male fertility and lifestyle, this is a conversation worth having – and an easy change worth making for the long term.

  1. Levine, 2022. Temporal trends in sperm count: a systematic review and meta-regression analysis – Human Reproduction Update. Source.
  2. Mínguez-Alarcón, 2018. Type of underwear worn and markers of testicular function among men attending a fertility center – Human Reproductive. Source.
  3. Ogle, 2019. Boxers or briefs? 4 common fertility myths debunked – Mayo Clinic. Source.
  4. Vij, 2019. Are You Unknowingly Lowering Your Sperm Count? When to Worry – Cleveland Clinic. Source.
  5. Healthline, 2025. Going Commando: Men and Women – Healthline. Source.
  6. Healthline, 2023. Tight Underwear: Pros & Cons, and Things to Consider – Healthline. Source.
  7. Rehman & Usman, 2018. Endocrine disrupting chemicals and impact on male reproductive health – Translational Andrology and Urology. Source.
  8. Wilson, 2022. Toxic Textiles: The Chemicals in Our Clothing – EarthDay.org. Source.
  9. WWF, 2023. Cotton – World Wildlife Fund. Source.
  10. Sanders, 2020. Bamboo: Eco-friendly fabric or environmental disaster? – Euronews. Source.
  11. Wallis, 2023. Common Chemicals May Harm Sperm and Pregnancies, Growing Evidence Shows – Scientific American. Source.