Core Daily Wrapped Liners vs Leak-Fighting Rotation Set Underwear: which is safer?

Kotex Core Daily Wrapped Liners is the clear pick. Thinx Leak-Fighting Rotation Set Underwear carries a failing PFAS grade, and we never recommend buying a failing product.

Our pick

Kotex Core Daily Wrapped Liners

Kotex

Core Daily Wrapped Liners

PFAS grade

Good 70/100

Overall grade

Poor 48/100

Verdict

Buy

Hazard flags

⚑ 4

Material

cotton, rayon, adhesive (nonwoven blend)

Confidence

72%

PossibleSynthetic adhesive leachables

ReportedFragrance allergens (if scented variant)

PossibleMicroplastic shedding from nonwoven backing

Thinx Leak-Fighting Rotation Set Underwear

Thinx

Leak-Fighting Rotation Set Underwear

PFAS grade

Poor 25/100

Overall grade

Bad 13/100

Verdict

Skip

Hazard flags

⚑ 3

Material

Cotton/synthetic blend with waterproof/moisture-wicking coating (unspecified chemistry)

Confidence

45%

PossibleFluorinated polymers (PFAS and PFAS-alternatives) in waterproof coating

PossibleCoating degradation and leachate release with heat or friction

PossibleMicroplastic shedding from synthetic blend and coating

Where these two actually differ

  • We flag Synthetic adhesive leachables, Fragrance allergens (if scented variant), Microplastic shedding from nonwoven backing and PFAS water-resistance coating (undisclosed) on the Kotex and not on the Thinx.
  • We flag Fluorinated polymers (PFAS and PFAS-alternatives) in waterproof coating, Coating degradation and leachate release with heat or friction and Microplastic shedding from synthetic blend and coating on the Thinx and not on the Kotex.
  • The Kotex is cotton, rayon, adhesive (nonwoven blend) where the Thinx is Cotton/synthetic blend with waterproof/moisture-wicking coating (unspecified chemistry), which is most of the difference in these two grades.
  • The gap is 45 points, wide enough that this is not a close call, and the Kotex is the one to buy.
  • We are less certain about the Thinx grade, at 45% confidence against 72%, because it discloses less.

Both products run through the same public rubric, which covers materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →

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