By Yahli, Founder of Wayve · 5 min read

The Fabric in Your Gym Shorts Is Linked to Lower Testosterone.

See why health-conscious men are replacing synthetic gym shorts with natural fibers.

Polyester sheds microplastics and leaches phthalates, BPA, and PFAS. Peer-reviewed studies link all three to lower testosterone and damaged sperm in men.

★★★★★ 31+ 5-Star Reviews

Shop the Quad Short

GOTS Certified Organic Cotton · OEKO-TEX 100 · Zero Synthetic Materials

Peer-reviewed research on what synthetic fabric does to the male endocrine system.

0

sperm count in all 14 men tested after 140 days of polyester contact. Reversed after removal.

Contraception, 1992

1% / year

decline in average male testosterone levels since the 1970s, independent of age.

J Clin Endocrinol Metab, 2007

22x

above California's safe limit for BPA found in polyester athletic wear from major brands.

Center for Environmental Health, 2023

We Built the Opposite of Plastic Activewear.

The Quad Short is built from two natural materials and nothing else. A 290GSM organic cotton shell. A 165GSM merino wool liner. No polyester, no nylon, no spandex, no chemical finishes. The fabric closest to your body is also the most hormonally neutral.

Organic Cotton Shell · 290GSM Merino Wool Liner · 165GSM Zero Synthetic Materials Made with GOTS-Certified Organic Cotton OEKO-TEX 100 Certified Dyes

What Our Customers Are Saying

★★★★★

"Noticeable difference in my energy levels"

Got my first full lift in today since buying these shorts and felt a noticeable difference in my energy levels. There is something about wearing natural fibers that amplifies your energy and these shorts give that feeling. The merino wool lining is insanely soft and gives a comfortable fit. The zipper pockets are nice because you don't have to worry about stuff falling out of your pockets.

★★★★★

"Insanely hard to find athletic wear not made of polyester. These are TOP TIER."

These shorts are the best! It's insanely hard to find athletic wear that is not made of polyester and these are TOP TIER. The wool lining is so soft and amazing to workout in. Also, the pockets being on the side are a huge plus. 10/10

★★★★★

"No better feeling than natural fibers against your skin"

There is no better feeling than clean, organic, natural fibers against your skin. These shorts make me happy.

The Evidence

Six peer-reviewed findings plus one active regulatory investigation. This is what the research says about polyester, microplastics, PFAS, and male hormonal health.

01

Lululemon Is Under Texas AG Investigation for PFAS in Activewear

April 2026 Texas AG Civil Investigative Demand issued

In April 2026, Texas Attorney General Ken Paxton issued a Civil Investigative Demand to Lululemon, opening an enforcement probe into whether the brand misled health-conscious customers about the presence of PFAS (forever chemicals) in its products. California and New York bans on PFAS in most apparel took effect in January 2025. The most recognizable activewear brand in the world is under state investigation for the same class of chemicals that peer-reviewed studies link to lower testosterone and poorer semen quality.

Texas Attorney General, April 13, 2026

02

Polyester Caused Zero Sperm Count in Every Man Tested

100% azoospermia after 140 days of polyester contact

Shafik's 1992 study in Contraception put 14 men in polyester scrotal slings. After roughly 140 days of contact, all 14 had zero sperm count. After removing the polyester, every man's sperm count returned. This is the most direct human evidence that polyester contact disrupts male reproduction.

Contraception, 1992 (Shafik)

03

Polyester Degraded Sperm Quality in Long-Term Exposure

0 adverse effects in the cotton control group

Shafik's 1993 follow-up in Urological Research kept dogs in polyester for 24 months. Sperm count dropped. Abnormal forms rose. The cotton control group showed zero adverse effects. When the polyester was removed, the damage reversed.

Urological Research, 1993 (Shafik)

04

Microplastics Are Accumulating in Human Testes

100% of human testes tested contained microplastics

The 2024 Toxicological Sciences paper found microplastics in 100% of human testes tested. Average concentration: 328.44 μg/g, nearly 3x the level found in dogs. Polyethylene was the dominant polymer. Polyester and polyethylene are two of the most common textile plastics.

Toxicological Sciences, 2024

05

Polyester Athletic Wear Tested 22x Above California's BPA Limit

22x above California's safe limit for BPA

The Center for Environmental Health's 2023 report detected BPA in polyester sportswear from major brands at levels well above California Prop 65 thresholds. BPA is one of the most well-characterized endocrine disruptors. The skin absorbs it. The heat of a workout accelerates the leaching.

Center for Environmental Health, 2023

06

PFAS Exposure Is Linked to Lower Testosterone and Poorer Semen Quality

Lower T and poorer semen quality tied to serum PFAS

Joensen 2009 in Environmental Health Perspectives tied serum PFAS levels in young men to reduced sperm quality and altered reproductive hormones. PFAS is the same class of forever chemicals routinely used in stain- and water-resistant synthetic textiles. It's the exact class Texas is investigating Lululemon over.

Environmental Health Perspectives, 2009 (Joensen)

07

There's a Short Built for the Opposite of All of This

0 synthetic materials

The Quad Short. Organic cotton shell, merino wool liner, zero synthetics. Made with GOTS-certified organic cotton. OEKO-TEX 100 certified dyes, verified free of harmful substances. No PFAS. No BPA. No phthalates. No plastic chemistry against your skin.

Why Natural Fiber Activewear

1

Zero Endocrine Disruptors

No phthalates, BPA, PFAS, or formaldehyde. Nothing leaching into your skin during a workout.

2

Zero Synthetic Materials

The only activewear short with no plastic, shell to liner. No microplastic shedding.

3

Merino Wool Liner Against the Skin

Naturally antimicrobial and temperature-regulating. The fabric closest to the body is also the most hormonally neutral.

4

GOTS-Certified Organic Cotton Shell

Third-party verified through the full production chain. No pesticide residue. No synthetic dyes.

5

OEKO-TEX 100 Dyes

Independently tested to be free of harmful substances. Verified, not marketed.

Quad Short vs. Polyester Performance Shorts

What's actually in your shorts.

Zero microplastic shedding

✓

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No phthalates, BPA, PFAS, or formaldehyde

✓

×

No endocrine disruptors against the skin

✓

×

GOTS-certified organic cotton

✓

×

Merino wool liner (naturally antimicrobial)

✓

×

Third-party audited supply chain

✓

×

Ready to take plastic off your skin?

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Quad Short: Natural Fiber Short

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★★★★★ (27)

Color: Black

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More From Our Customers

★★★★★

"Best athletic shorts ever"

Best athletic shorts I have ever purchased. The quality of these shorts is top-notch. I purchased the Wine color and it's a beautiful shade. The zippered pockets are a fantastic feature, no more worrying about your phone or keys falling out during a workout. I would recommend sizing up one size for a more relaxed fit.

★★★★★

"Finally, not just rebranded plastic"

Really impressed with the quality of these shorts compared to synthetic alternatives. The organic cotton feels premium and durable. I've put them through multiple washes and workouts and they hold up great. Finally an activewear brand that's not just selling rebranded plastic.

★★★★★

"Phasing out all my other shorts for these"

Came back for my second pair. I'm phasing out all my other shorts for these. The durability has been excellent. First pair still looks and feels brand new after months of regular use.

★★★★★

"All natural fibre training short, super comfortable"

Finally found an all natural fibre training short. Super comfortable for lifting and conditioning work. The merino liner wicks moisture really well. No clamminess even during intense sessions.

I started looking into what my gym clothes were actually made of. I didn't like what I found.

Every pair of shorts in my drawer was polyester. Shedding microplastics. Coated in chemicals I couldn't pronounce. I train hard, and I care about my hormones, my fertility, and my long-term health. I didn't want the fabric I sweat into six days a week working against all of that.

So I built the Quad Short. Organic cotton shell, merino wool liner, zero synthetics. No plastic. No compromise.

— Yahli, Founder

Frequently Asked Questions

Does polyester really affect testosterone? +

The most direct evidence comes from Shafik's 1992 study in Contraception: 14 men wore polyester scrotal slings for ~140 days and all 14 went to zero sperm count. It reversed after removal. A 1993 follow-up in Urological Research replicated the effect in dogs over 24 months, with a cotton control group showing zero adverse effects. Separately, PFAS (a class of chemicals used in some synthetic activewear) has been tied to reduced testosterone and semen quality in Joensen 2009 (Environmental Health Perspectives). The evidence is strongest for direct polyester contact and PFAS exposure. Natural fibers remove both variables.

What are the endocrine-disrupting chemicals in synthetic activewear? +

The main three are PFAS (used in stain- and water-resistant finishes), BPA (found 22x above California's safe limit in polyester athletic wear per the Center for Environmental Health, 2023), and phthalates (commonly used as plasticizers). All three are classified as endocrine disruptors. The skin absorbs them, and heat and sweat accelerate that absorption. The Texas Attorney General opened an investigation into Lululemon in April 2026 specifically over PFAS in activewear.

Is organic cotton durable enough for intense training? +

Yes. The Quad Short uses a 290GSM brushed terry construction, significantly heavier than typical synthetic shorts. Our customers lift, run, and train in them without issue. The fabric gets softer with wear while maintaining its structure.

How does merino wool compare to synthetic liners? +

Merino wool naturally wicks moisture, resists odor, and regulates temperature. The 165GSM merino liner delivers the functional performance of synthetic liners with no chemical antimicrobial treatments required. Modern merino fibers are fine enough to feel soft against the skin, not scratchy.

What certifications back up your claims? +

The Quad Short is made with GOTS-certified organic cotton, the gold standard for organic textiles. Dyes are OEKO-TEX 100 certified, independently verified to be free of harmful substances. Both certifications are held by our manufacturer and audited by third parties.

What's the return policy? +

7-day returns from delivery. Item must be unworn with tags attached. Free shipping on US orders over $150. Contact info@wayvewear.com to start a return.

Stop Training in Plastic.

The Quad Short. Organic cotton shell. Merino wool liner. Zero synthetics. Zero endocrine disruptors.

Buy 3, Save 21% · Free Shipping $150+

Shop the Quad Short (15% Off) or try the 3-Pack and save $20 →

Free 7-Day Returns Free Shipping $150+ Zero Synthetics