Period Underwear (Hiphugger)

Name: Period Underwear (Hiphugger)
Brand: Thinx

PFR Grade

Fair — some plastic content or limited transparency

PFAS detected in Thinx products in 2020 testing. Thinx settled a class action lawsuit in 2023 over PFAS in their products. Thinx has reformulated to remove PFAS from new products, but transparency remains a concern.

PFR Reviewed

Period underwear. Thinx settled a PFAS class action lawsuit in 2023. Thinx has reformulated to remove PFAS from new products.

Score Breakdown

How scores are calculated

Materials (40%): How plastic-free the product is — raw materials, construction, and coatings.

Packaging (20%): Is the product packaged in plastic? Is it recyclable?

Transparency (20%): Does the brand disclose ingredients, sourcing, and manufacturing?

Durability (20%): How long does it last? Longer-lasting products reduce plastic waste over time.

Materials

Packaging

Transparency

Durability

$35See Safer Alternatives in Feminine Care

This is a rating of this specific product only — not the company. Other products from this brand may score differently.

Last updated: April 6, 2026

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High Exposure Risk — Why This Product Category Matters

Conventional tampons and pads contain pesticide residues (cotton is one of the most heavily pesticide-treated crops), dioxins from chlorine bleaching, and synthetic fragrances. The vaginal mucosa is one of the most absorptive surfaces in the body — chemicals applied to this area absorb directly into the bloodstream.

Synthetic Plastic Content

50%

synthetic plastic by weight

Why We Rated It This Way

Thinx settled a class action lawsuit in 2023 over PFAS detected in their period underwear. Thinx has since reformulated to remove PFAS from new products. If purchasing Thinx, look for products manufactured after 2023 and verify PFAS-free claims.

Chemical & Health Analysis

Each chemical of concern is broken down below — what it is, where it comes from in this product, what it does to the body, and who is most at risk.

Contains:Synthetic fabric

PFAS

Source

PFAS detected in Thinx period underwear (pre-2023 formulation)

Health Risk

Endocrine disruption, possible carcinogen

Who Is Most At RiskWomen using Thinx period underwear (pre-2023 formulation)

Peer-Reviewed Sources

All health claims are based on published, peer-reviewed research from the NIH, WHO, IARC, and peer-reviewed journals. This information is for educational purposes and does not constitute medical advice.