Thinx Period Underwear Lawsuit, What the $5 Million Settlement Reveals About PFAS in Your Intimates
Thinx settled a class action lawsuit for up to $5 million after customers claimed the company’s period underwear contained toxic PFAS chemicals—despite marketing the products as safe, organic, and free from harmful substances. The settlement covers purchases made between November 12, 2016, and November 28, 2022. The claims deadline has passed (April 12, 2023), and payments have been distributed. If you missed the deadline, you cannot claim compensation from this settlement.
What the Lawsuit Alleged
In May 2022, customers filed a federal class action in the U.S. District Court for the Southern District of New York (Case No. 1:22-cv-4286-JMF). The lawsuit accused Thinx of:
Deceptive Marketing: Third-party testing revealed high levels of PFAS in Thinx underwear. The inside crotch area of one pair tested at 3,264 parts per million of fluorine (an indicator of PFAS)—levels suggesting intentional use. Yet Thinx claimed its products were “rigorously tested” and “free of harmful chemicals.”
Contradictory Statements: Thinx’s website once stated: “Are Thinx free of harmful chemicals? Absolutely!” The company also claimed chemicals used in its anti-odor layer “stay on the surface of the underwear and don’t travel into your body.” These claims disappeared from the website around May 2021.
Agion Anti-Microbial Treatment: The lawsuit alleged Thinx used Agion, an antimicrobial treatment made from silver and copper nanoparticles, contradicting its claims that products were free from “non-migratory nanoparticles.”
How the PFAS Was Discovered
In January 2020, Sierra magazine reporter Jessian Choy sent unused Thinx underwear to Dr. Graham Peaslee, a nuclear physicist at the University of Notre Dame who previously discovered PFAS in fast-food wrappers. His lab found:
- Thinx organic brief: 3,264 ppm of fluorine
- Thinx organic Shorty for teens: 2,053 ppm of fluorine
These levels were high enough to suggest PFAS was intentionally added during manufacturing. After the article published, Thinx CEO Maria Molland released a statement claiming testing confirmed “no detectable long-chain PFAS chemicals.” The lawsuit alleged this statement misrepresented the testing results and further misled customers.
What Are PFAS?
Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals used since the 1940s in consumer products like:
- Nonstick cookware
- Water-repellent clothing
- Firefighting foams
- Food wrappers
- Cosmetics
PFAS are called “forever chemicals” because they don’t break down in the environment or in human bodies. The CDC links high PFAS exposure to:
- Increased cholesterol levels
- Changes in liver enzymes
- Decreased vaccine response in children
- Increased risk of kidney or testicular cancer
- Fertility issues
- Pregnancy complications
PFAS in menstrual underwear raises particular concern because the vaginal area is highly absorbent, potentially allowing chemicals to enter the bloodstream.
Thinx’s Response
Thinx denied all allegations and admitted no wrongdoing. In a statement, the company said:
“Consumer health and product safety are top priorities for Thinx, and we stand by the quality, efficacy and safety of our products. The lawsuit is related to how products were marketed and not on product safety or any adverse health effects. PFAS has never been part of the brand’s product design and we continue to take measures to help ensure these substances are not added to our products.”
The Settlement Terms
The settlement received final court approval on June 8, 2023. Here’s what was included:
Cash Fund: Thinx agreed to pay $4 million minimum, with an additional $1 million available if needed to cover all valid claims.
Compensation Options: Customers could choose between:
- Cash refund: $7 per pair (with proof of purchase) or $3.50 per pair (without proof), up to 3 pairs maximum
- Voucher: 35% off future purchases up to $150 (maximum discount $52.50)
Covered Products: Cotton Brief, Cotton Bikini, Cotton Thong, Sport, Hiphugger, Hi-Waist, Boyshort, French Cut, Cheeky, and Thong styles purchased between November 12, 2016, and November 28, 2022.
Settlement Payouts: Reports indicate the settlement paid out approximately $10.50 to claimants without proof of purchase as of July 2023.
What Laws Apply
The lawsuit was based on:
Consumer Protection Laws: Federal and state laws prohibiting deceptive marketing practices and false advertising.
Product Liability Principles: Claims that Thinx failed to disclose the presence of harmful chemicals in products marketed as safe and organic.
Fraud and Misrepresentation: Allegations that Thinx knowingly made false statements about product safety and chemical content.
Similar Cases
Thinx wasn’t alone. Other period underwear brands faced similar scrutiny:
Knix: Settled a separate PFAS lawsuit for up to $2 million. Customers who purchased Knix products could receive up to $5.30 per pair (maximum $15.90 for three pairs). The settlement received final approval in April 2024.
Industry Testing: After Thinx revelations, consumer advocacy group Mamavation tested 14 period underwear brands. About 65% tested positive for fluorine in the crotch area. Testing found PFAS not only in period underwear but also in menstrual pads, tampons, and menstrual cups.
What This Means for Consumers
Settlement Deadline Passed: If you purchased Thinx underwear between November 2016 and November 2022, you cannot file a claim now. The April 12, 2023 deadline has passed, and payments have been distributed.
Future Legal Action: The settlement specifically addressed marketing claims—not health injuries. If you developed health problems you believe are related to Thinx products, the settlement does not prevent you from filing a personal injury lawsuit.
Ongoing Commitments: As part of the settlement, Thinx agreed to continue taking measures to ensure PFAS are not intentionally added to its products at any stage of production.
Broader Implications
First PFAS Consumer Products Settlement: The Thinx settlement was the first class action alleging deceptive marketing practices based on PFAS in consumer products. It set a precedent for holding companies accountable for misleading claims about product safety.
State Regulations: California now prohibits textiles from containing PFAS at or above 100 ppm starting January 1, 2025 (lowering to 50 ppm in 2027), even if PFAS is not intentionally added.
Disclosure Laws: New York requires menstrual product manufacturers to disclose ingredients, though testing is not required. Advocates push for stronger laws requiring actual product testing.
Corporate Ownership: Since 2022, Thinx has been majority owned by Kimberly-Clark, which also owns Kotex, Huggies, and Scott brands. The $5 million settlement represents a small fraction of the parent company’s revenue.
What Legal Experts Say
Attorney Erin Ruben, who represented plaintiffs, told NPR: “This is the first class action case that we are aware of to allege deceptive marketing practices stemming from the presence of PFAS in consumer products. The settlement was about the marketing of the underwear—not whether it caused harm to consumers.”
Harvard T.H. Chan School of Public Health assistant professor Shruthi Mahalingaiah noted: “If I, someone with expertise, still have difficulties identifying what’s safe for my children, I don’t suspect it’s any easier for anyone else.”
Timeline of Key Events
January 2020: Sierra magazine publishes investigation revealing PFAS in Thinx underwear
November 2020: First lawsuit filed against Thinx
May 2022: Class action lawsuit filed in federal court (Dickens v. Thinx Inc.)
November 28, 2022: Court grants preliminary approval of settlement
January 2023: Settlement website goes live; claims period opens
April 12, 2023: Claims deadline
June 8, 2023: Court grants final approval
July 2023: Settlement payments begin distribution
FAQ
Q: Can I still file a claim?
No. The claims deadline was April 12, 2023. Payments have already been distributed.
Q: Did Thinx admit wrongdoing?
No. The settlement includes no admission of guilt or wrongdoing. Thinx maintains PFAS were never part of its product design.
Q: Are current Thinx products safe?
Thinx states it takes measures to ensure PFAS are not intentionally added to products. However, independent testing after the settlement has not been widely published.
Q: What if I developed health problems from wearing Thinx?
The settlement specifically preserves your right to file personal injury claims. Consult an attorney specializing in product liability or toxic tort litigation.
Q: Which other brands tested positive for PFAS?
Testing by Mamavation found approximately 65% of period underwear brands contained fluorine. Only Aisle brand tested negative for PFAS in multiple independent tests.
Q: How much PFAS exposure is dangerous?
The EPA recommends drinking water contain no more than 0.004 parts per trillion for PFOA and 0.02 ppt for PFOS. However, these limits don’t directly translate to exposure through clothing worn against skin.
Q: Should I throw away my Thinx underwear?
That’s a personal decision. If you’re concerned about PFAS exposure, consider switching to brands that have tested negative for these chemicals or traditional menstrual products.
The Thinx settlement closed a chapter on one of the first major consumer lawsuits addressing PFAS in products marketed as safe and sustainable. While the financial payout was modest, it sparked broader conversations about chemical safety in products that contact intimate areas of the body—and about holding companies accountable when their marketing doesn’t match reality.
About the Author
Sarah Klein, JD, is a licensed attorney and legal content strategist with over 12 years of experience across civil, criminal, family, and regulatory law. At All About Lawyer, she covers a wide range of legal topics — from high-profile lawsuits and courtroom stories to state traffic laws and everyday legal questions — all with a focus on accuracy, clarity, and public understanding.
Her writing blends real legal insight with plain-English explanations, helping readers stay informed and legally aware.
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