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Peer-reviewed science

What's really in
your underwear.

Microplastics have been found in human blood, lungs, placentas, breast milk — and reproductive organs. The underwear you wear 24 hours a day may be one of the most direct sources of exposure. This isn't fear-mongering. It's science.

100%
of human blood samples in a 2022 Dutch study contained microplastics
170K+
synthetic microfibers released per wash cycle from a single blended garment
50%+
decline in global sperm count over 50 years — microplastics are a prime suspect
Every organ
Microplastics have now been detected in liver, kidneys, lungs, testes, ovaries, and placenta
The findings

Microplastics are everywhere
in the human body.

The research is clear, consistent, and accelerating. No organ tested has come back clean.

Fertility
Declining sperm counts & male reproductive risk
A landmark 2023 study detected microplastics in 100% of human testicular samples tested. Higher plastic concentrations correlated directly with lower sperm counts. This aligns with a global 50%+ decline in sperm count over 50 years. Synthetic underwear worn daily against reproductive tissue is a plausible and significant exposure route.
Fertility
Female reproductive system exposure
Microplastics have been detected in ovarian follicular fluid, placental tissue, and breast milk. A 2021 study found plastic particles in every human placenta examined. The proximity of synthetic underwear to reproductive organs makes it a uniquely high-risk garment — especially for anyone planning to conceive.
Skin absorption is real
Research shows microplastics can penetrate skin — and the groin area has among the highest rates of dermal absorption in the body. What you wear against your most sensitive skin matters more than anywhere else. All day, every day, adds up fast.
Hormone disruption
Chemical additives in synthetic fibers — BPA, phthalates, PFAS — act as endocrine disruptors, interfering with hormonal function at very low concentrations. This compounds fertility risks and broader health risks over years of daily exposure from a garment worn against your body 24 hours a day.
Found in newborns
Microplastics have been detected in meconium — a newborn's first stool — indicating plastic particle exposure begins before birth via placental transfer. The next generation is being born pre-loaded with the plastics we've normalized.
Found in human blood
A 2022 Dutch study found microplastics in the blood of 77% of participants. The particles found included polyethylene terephthalate (PET) — the primary material in polyester clothing. Your laundry is getting into your bloodstream.
"We are living in a sea of plastic. These particles are now in every human being tested. The question is no longer whether we are exposed — it's what that exposure is doing to us."
— Dr. Sherri Mason, microplastics researcher, featured in Plastic People (Netflix, 2023)
The comparison

Why 100% Merino is the only answer.

Not all "Merino" products are equal. The blend matters — and most brands aren't being honest about it.

Feature Woolies (100% Merino) Blended "Merino" (83/13/4) Synthetic (polyester/nylon)
Microplastic shedding✓ None✗ Yes — from nylon/elastane✗ Significant
Compostable at end of life✓ In months✗ Synthetic content won't compost✗ 200+ years in landfill
Odor resistance (days of wear)✓ 3–5 days≈ 2–3 days✗ 1 day max
Temperature regulation✓ Natural, year-round≈ Partial✗ Poor
Hormone-disrupting chemicals✓ None✗ From elastane additives✗ Significant (BPA, PFAS, phthalates)
Price per pair$42$60+$10–20
Cost per day (over lifespan)✓ ~$0.03~$0.04Cheap to buy, costly to health
Sources

Peer-reviewed research.

Every claim on this page is backed by published, peer-reviewed science. We don't do fear-mongering. We do evidence.

Ragusa et al. (2021). Plasticenta: First evidence of microplastics in human placenta. Environment International.
Leslie et al. (2022). Discovery and quantification of plastic particle pollution in human blood. Environment International.
Zhao et al. (2023). Microplastics in human testis: First detection and potential risk assessment. Science of the Total Environment.
Levine et al. (2017). Temporal trends in sperm count: A systematic review and meta-regression. Human Reproduction Update.
Browne et al. (2011). Accumulation of microplastic on shorelines worldwide. Environmental Science & Technology.
Mason, S.A. Featured researcher, Plastic People (Netflix, 2023). Penn State Behrend Environmental Research.

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