The Short Answer
Thinx revolutionized period care, but their safety record is deeply flawed. In 2023, the brand settled a $4 million class-action lawsuit after independent tests found high levels of toxic PFAS in their underwear.
Today, Thinx holds strict OEKO-TEX certifications and tests free of forever chemicals. However, their historical use of Agion silver antimicrobial treatments means we still urge caution. Is Period Underwear Safe
Why This Matters
The skin around your vulva and vagina is exceptionally thin and highly permeable. Whatever touches this tissue goes directly into your bloodstream without being filtered by your liver first.
In 2020, independent testing by the Sierra Club and Mamavation revealed a massive betrayal of consumer trust. They found up to 3,267 ppm of fluorineāan indicator of PFASāin the crotch of Thinx organic briefs. Does Thinx Have Pfas
PFAS are known as "forever chemicals" because they don't break down in your body or the environment. They are linked to cancer, decreased fertility, and immune system disruption. Is There Pfas In Period Underwear
While Thinx has cleaned up their PFAS problem, their odor-control technology is another concern. The brand has historically used Agion, a silver-based antimicrobial treatment that can disrupt your healthy vaginal microbiome.
What's Actually In Thinx
- PFAS (Forever Chemicals) ā Historically found in high levels (up to 3,267 ppm) in the absorbent gusset, though current manufacturing tests PFAS-free. Which Period Underwear Has Pfas
- Agion Silver Treatment ā An antimicrobial heavy metal used for odor control that can migrate into your body and kill beneficial vaginal bacteria. Is Silver In Period Underwear Safe
- Conventional Elastane and Nylon ā Synthetic petroleum-based fabrics used for stretch and leak-proofing, which can trap heat and moisture.
What to Look For
Green Flags:
- Third-party lab testing ā Brands should publish their actual chemical test results, not just make empty marketing claims.
- Silver-free gussets ā Your period underwear doesn't need heavy metals to control odor; washing them properly is enough. Safest Period Underwear
Red Flags:
- "Antimicrobial" marketing ā This is almost always a code word for silver nanoparticles or chemical biocides.
- Proprietary odor tech ā If a brand won't tell you exactly how they stop odors, they are hiding something.
The Best Options
If you want leakproof protection without the chemical baggage, you have better options. We highly recommend switching to brands with full transparency. Period Underwear No Pfas
| Brand | Product | Verdict | Why |
|---|---|---|---|
| Period Aisle | Period Boxers | ā | Completely silver-free and transparently publishes PFAS test results. |
| Saalt | Period Underwear | ā | PFAS-free with zero silver or biocides used in their gussets. Is Saalt Period Underwear Clean |
| Thinx | Classic Briefs | ā ļø | Current models are PFAS-free, but their history and use of silver treatments require caution. |
| Knix | Leakproof Underwear | ā ļø | Settled their own PFAS lawsuit, making them hard to fully trust. Is Knix Clean |
The Bottom Line
1. Throw away your old Thinx. If you bought pairs between 2016 and 2022, they likely contain high levels of PFAS and should not be worn.
2. Avoid "antimicrobial" treatments. Look for brands that explicitly state they do not use silver nanoparticles or biocides in their gussets.
3. Switch to transparent brands. Companies like Saalt and Period Aisle prove you can make effective period underwear without toxic chemicals. Safest Period Underwear
FAQ
Do new Thinx still have PFAS?
No, current testing shows Thinx are now free of forever chemicals. They achieved OEKO-TEX Standard 100 Class II certification, which requires rigorous testing for PFAS and other toxins. Does Thinx Have Pfas
Is the silver in Thinx safe?
We don't think so. The lawsuit forced Thinx to admit their Agion silver treatment is not "non-migratory," meaning these heavy metals can transfer from the fabric into your body. Is Silver In Period Underwear Safe
Can I get a refund for my old Thinx?
The deadline to file a claim for the $4 million class-action settlement passed in April 2023. If you still have old pairs, your safest option is to throw them in the trash.