Thinx Review, Is Thinx 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 8 graded products, Thinx 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
Thinx
Intimates & Sleepwear Thinx for All Women's Period Underwear
Nylon, spandex, cotton blend with waterproof barrier layer
PFAS
Thinx's 2021 lawsuit settlement involved PFAS contamination; the company has not…
Azo dyes in synthetic fibers
Nylon and spandex blends may be dyed with azo compounds, which can produce allergenic…
Microplastics
Nylon and spandex are microplastic sources when mechanically stressed (washing, wear).…
Coating adhesion and leaching as barrier degrades
No manufacturer data on barrier lifespan; typical waterproof fabric coatings begin to…
Skip until Thinx reveals waterproof coating chemistry and testing.
⚠Waterproof or stain-proof treatment
Thinx
Make The Switch Set Period Underwear
Cotton/synthetic blend with waterproof coating (composition unspecified)
PFAS
Undisclosed waterproofing layer is most probable PFAS source. Brand silence and industry…
Microplastic shedding from synthetic coating
Waterproof synthetic layers on textiles shed microfibers and polymer particles during…
Formaldehyde / VOCs
Cotton-blend textiles are often treated with formaldehyde-releasing resins for wrinkle…
Coating degradation and leachate into body
Owners report visible peeling and stiffening of waterproof layer after 12-18 months of…
Skip until Thinx discloses waterproofing agents and testing data.
⚠Waterproof or stain-proof treatment
Thinx
Cotton Starter Set Period Underwear
Cotton + proprietary waterproof/absorbent layer coating
PFAS
Already graded separately at Poor (25/100). Thinx has not disclosed coating chemistry…
Coating degradation and particle shedding
Proprietary multilayer coatings can degrade with heat, detergent buildup, or age. Thinx…
Bacterial growth if moisture is trapped
Any absorbent intimate textile risks bacterial overgrowth if not fully air-dried. Thinx…
Moderate concern without waterproof coating transparency.
⚠Waterproof or stain-proof treatment
Thinx
Cotton Overnight Set Period Underwear
Cotton with water-resistant membrane/lining layer (composition unspecified)
PFAS
The membrane composition is not publicly identified. Period underwear waterproofing…
Formaldehyde / VOCs
Textiles sometimes use formaldehyde-releasing resins for durable finishes or wrinkle…
Membrane degradation and microplastic shedding
If the waterproof layer is a synthetic polymer (polyurethane or Teflon-type…
Allergic contact dermatitis from undisclosed additives
Waterproof membranes, adhesives, and dyes can trigger reactions in sensitive users.…
Skip until Thinx discloses waterproofing agent; period underwear often uses PFAS-based water-repellent coating.
⚠Waterproof or stain-proof treatment
Thinx
for All Women's Comfort Brief Leakproof Period Underwear
nylon/spandex blend with proprietary waterproof absorption layer
PFAS
Leakproof period underwear commonly relies on fluorinated water-repellent finishes; Icon…
Leakproof treatment unclear; brand silent on PFAS.
⚠Waterproof or stain-proof treatment
Thinx
Leak-Fighting Rotation Set Underwear
Cotton/synthetic blend with waterproof/moisture-wicking coating (unspecified chemistry)
Don't buy until the brand reveals the waterproof coating material; period underwear's leak-fighting layer is a common PFAS concern.
⚠Waterproof or stain-proof treatment
Thinx
Speax by Thinx Thong Incontinence Underwear Women for
Moisture-wicking synthetic blend with unspecified waterproof/absorbent coating
Don't buy until the brand clarifies the waterproof coating material; likely PFAS risk unaddressed.
⚠Waterproof or stain-proof treatment
Thinx
Leak-Fighting Cotton Brief Underwear
Cotton blend with waterproof gusset coating (unspecified)
Don't buy until Thinx reveals the gusset treatment material or obtains third-party verification.
⚠Waterproof or stain-proof treatment
Every grade uses the same public rubric. How grades work →