Proof Review, Is Proof Non-Toxic?
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.
Across 4 graded products, Proof averages Poor (25/100). On disclosure, the brand says nothing publicly about PFAS. None of its products grade Good or better yet. Grades are model-based estimates, not lab results.
Graded and flagged Poor and Bad, we’d swap these
Proof
No Boundaries Boyshort Super Absorbency Period Underwear 2-Pack Womens
Cotton blend with water-resistant coating
PFAS
Period underwear waterproof layers typically rely on fluorochemical chemistry; Proof's…
Microfiber shedding from synthetic coating
Degradation of the water-resistant layer over time and with washing can release…
Bacterial growth under waterproof barrier if poorly maintained
The occlusive nature of the water-resistant coating can trap moisture and bacteria…
Coating leaching into skin or bloodstream via absorption
Direct prolonged contact with water-resistant coating on mucous-adjacent skin may allow…
Period absorbent underwear; waterproof coating creates PFAS risk.
⚠Waterproof or stain-proof treatment
Proof
Saalt Leakproof Period Cotton Brief, Heavy / S / Pink Dawn
organic cotton with waterproof coating (unspecified)
Unspecified waterproof coating chemistry
Proof has not disclosed whether the waterproof layer uses PFAS, alternative polymers, or…
Coating degradation and microparticle shedding
Waterproof coatings degrade with repeated washing and heat. If the coating flakes or…
Skin irritation or sensitization from finish chemicals
Undisclosed coating chemistry and direct, prolonged skin contact create potential for…
Organic cotton base is lower concern; waterproof coating unspecified and unexplained.
⚠Waterproof or stain-proof treatment
Proof
Hanes Women's Comfort Period. Brief Underwear
cotton blend with unspecified moisture/stain resistant coating
PFAS
Stain and moisture-resistant finishes on textiles typically rely on PFAS chemistry.…
Coating degradation and leaching with wear
All topical textile coatings degrade over time and with washing. If the coating contains…
Formaldehyde / VOCs
Cotton-blend textiles sometimes use formaldehyde-containing resins in wrinkle-resistance…
Skin irritation or sensitization from coating additives
Proprietary coating chemistry may include plasticizers, adhesion agents, or catalysts not…
Skip until brand discloses coating chemistry and PFAS status.
⚠Waterproof or stain-proof treatment
Proof
Thinx Teens Bikini Leakproof Period Underwear - Black
Gusseted cotton-blend fabric with water-resistant coating
Coating degradation and particle shedding
water-repellent coating coatings on textiles naturally degrade with repeated washing and…
Formaldehyde / VOCs
Cotton-blend fabrics may be treated with formaldehyde-releasing resins for shape…
Azo dyes in black fabric
The black colorant may use azo dyes, which can release carcinogenic amines under certain…
Allergen irritation from undisclosed additives
Antimicrobial or anti-odor finishes are common in period underwear but often not itemized…
Leakproof underwear likely uses water-repellent coating.
⚠Waterproof or stain-proof treatment
Every grade uses the same public rubric. How grades work →