Thinx Review, Is Thinx Non-Toxic?
Thinx averages 25 out of 100 on PFAS Authority's PFAS and toxin screen across the 12 Thinx products graded as of October 2026, and none of them reach its 70 point pass mark.
Thinx grades Poor on our four-band scale.
PFAS Authority is a scoring system, not a laboratory. We do not test products ourselves. Grades are model-based, built from published ingredients, materials, certifications, brand disclosures and third-party lab results where they exist. See the rubric.
What Thinx says and does about PFAS
Thinx settled a class action over PFAS in its period underwear in the Southern District of New York. The plaintiffs’ settlement filing describes a fund of up to $5 million, and under the settlement Thinx agreed to measures that require its suppliers to attest that PFAS are not intentionally added to Thinx period underwear. The settlement is not an admission of wrongdoing. Minnesota’s ban on intentionally added PFAS in menstruation products covers period underwear.
- Legal caseThinx settled a class action in the Southern District of New York over PFAS in its period underwear, with a settlement fund of up to $5 million according to the plaintiffs’ settlement filing. Plaintiffs’ filing via ClassAction.org ↗
- Legal caseUnder that settlement Thinx agreed to measures that require suppliers to attest that PFAS are not intentionally added to its period underwear, and the settlement is not an admission of wrongdoing. Thinx settlement site (archived page) ↗
- Regulatory filingMinnesota’s ban on intentionally added PFAS, in force since 2025, covers menstruation products such as pads, tampons, period underwear and menstrual cups. Minnesota Pollution Control Agency ↗
Sources checked September 14, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.
Thinx is one of the brands we researched by hand for our record of what every brand has published about PFAS, where the same question is answered for each of them in one line.
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Does Thinx have PFAS, by category
Which Thinx products contain PFAS? Poor and Bad, we’d swap these
- Nylon, spandex, cotton blend with waterproof barrier layer
- PFAS. Thinx's 2021 lawsuit settlement involved PFAS contamination; the company has not disclosed current…
5 hazards checked on this product, all on its full breakdown.
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- Cotton with water-resistant membrane/lining layer (composition unspecified)
- PFAS. The membrane composition is not publicly identified. Period underwear waterproofing typically relies on…
4 hazards checked on this product, all on its full breakdown.
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- Cotton + proprietary waterproof/absorbent layer coating
- PFAS. Already graded separately at Poor (25/100). Thinx has not disclosed coating chemistry; undisclosed…
3 hazards checked on this product, all on its full breakdown.
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- Cotton/synthetic blend with waterproof/moisture-wicking coating (unspecified chemistry)
- PFAS. The unspecified moisture barrier in Thinx underwear is highly likely to contain fluorinated chemicals…
3 hazards checked on this product, all on its full breakdown.
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- Cotton/synthetic blend with waterproof coating (composition unspecified)
- PFAS. Undisclosed waterproofing layer is most probable PFAS source. Brand silence and industry norms suggest…
4 hazards checked on this product, all on its full breakdown.
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- nylon/spandex blend with proprietary waterproof absorption layer
- PFAS. Leakproof period underwear commonly relies on fluorinated water-repellent finishes; Icon has not…
- Moisture-wicking synthetic blend with unspecified waterproof/absorbent coating
- Coating degradation and leachate release. The unspecified waterproof coating may degrade over time with…
2 hazards checked on this product, all on its full breakdown.
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- Cotton blend with waterproof gusset coating (unspecified)
- PFAS. Gusset coating chemistry is unspecified; PFAS-based water-repellent coating finishes are industry…
3 hazards checked on this product, all on its full breakdown.
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- gusset fabric with moisture-wicking treatment, composition unspecified
- Formaldehyde / VOCs. Moisture-wicking treatments in textiles commonly use formaldehyde-releasing resins or…
4 hazards checked on this product, all on its full breakdown.
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- Cotton/synthetic blend with proprietary waterproof coating
- Waterproof coating composition (undisclosed). The proprietary waterproof layer is not publicly named or…
2 hazards checked on this product, all on its full breakdown.
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- Cotton blend with proprietary water-resistant coating (unspecified)
- Proprietary water-resistant coating composition undisclosed. Thinx has not named the coating chemistry…
3 hazards checked on this product, all on its full breakdown.
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- Cotton blend with unspecified water-repellent coating
- Undisclosed water-repellent coating chemistry. Thinx does not disclose the chemical family of its coating…
5 hazards checked on this product, all on its full breakdown.
Find an alternative on AmazonWhat to buy instead Good or better, in the categories Thinx sells
- organic cotton, waterproof backing layer
- A third party reports verifying it as PFAS-free
- Coating degradation and microparticle shedding
2 hazards checked on this product, all on its full breakdown.
- organic cotton blend, water-resistant gusset
- The brand calls it PFAS-free, which we have not verified
- Microplastic shedding from water-resistant barrier
- Organic cotton, wood pulp fiber
- The brand calls it PFAS-free, which we have not verified
- Azo dyes and synthetic dyes
2 hazards checked on this product, all on its full breakdown.
Thinx and PFAS, common questions
- Does Thinx have PFAS?
- Thinx averages 25 out of 100 on PFAS Authority's PFAS and toxin screen across the 12 Thinx products graded as of October 2026, and none of them reach its 70 point pass mark. Grades are model-based estimates built from published materials, ingredients and disclosures, not lab tests. Thinx settled a PFAS class action without admitting wrongdoing, and agreed to require suppliers to attest that PFAS are not intentionally added to its period underwear.
- Is Thinx non-toxic?
- No Thinx product we graded reaches Good. The best of them is Thinx Intimates & Sleepwear Thinx for All Women's Period Underwear at 25/100.
- Which Thinx products should I avoid?
- The lowest-graded Thinx products we have scored are Thinx Women Intimates & Sleepwear Thinx Hiphugger Period Black, Thinx For All Period Underwear Size M - New Women | Color: Red/Brown, (2 pack) Thinx for All Period Underwear for Women, Super Absorbency, Black, S-xl, Women's, Size: Small. Each one links to the evidence behind its grade.
Every grade uses the same public rubric. How grades work →