Period Care Reviewed Jul 5, 2026

Thinx

The period-underwear pioneer — bought by Kimberly-Clark, and it settled a PFAS class action.

Settlement · 2023 · resolved

PFAS class-action settlement (Dickens v. Thinx)

After independent testing (Sierra Club / Dr. Graham Peaslee, 2020) detected PFAS "forever chemicals" in Thinx period underwear despite its non-toxic marketing, a class action (Dickens v. Thinx) settled in 2023 for up to ~$5M. Thinx denied wrongdoing and agreed to take measures to ensure PFAS are not intentionally added to its products.

Source →

Our take

Why It’s on Our Radar

We don't recommend it as a clean pick. It's conglomerate-owned and settled a class action after independent testing found PFAS in products marketed as non-toxic. It's here as a cautionary reference, with founder-owned, PFAS-tested alternatives above.

What's inside

Ingredients & Safety

Marketed as non-toxic, but independent 2020 testing detected PFAS "forever chemicals," and the brand settled a class action over it in 2023 (agreeing to steps to avoid intentionally-added PFAS going forward).

No listed ingredient is currently on our watch or caution list. This finding applies only to the ingredient list shown below and may not cover every product, variant, market, or reformulation.

Ingredient List Reviewed

Safe Watch Caution
  • Nylon
  • Elastane
  • Cotton Lining

Formula scope: the disclosed ingredient list captured for this review. Formulas can differ by product, scent, country, and date; compare the current package with this list before deciding.

Want another top-tier option? Natracare in Period Care currently meets our top criteria. Review its formula scope and cited records before deciding.

Who owns it

Ownership & Independence

Kimberly-Clark acquired a majority stake in Thinx in 2022 and completed the acquisition in 2024. Thinx is no longer independent.

Where to buy

Key Products

As an Amazon Associate, we earn from qualifying purchases. Commissions never influence scores.

Check the exact formula, size, seller, and availability on Amazon. Search links show results that may include other brands. Links open in a new tab.