Women's Asymmetric Double-Faced Swimsuit vs Women's Bottom Turn Racerback Bikini Top: which is safer?
Patagonia Women's Bottom Turn Racerback Bikini Top is the clear pick. COS Women's Asymmetric Double-Faced Swimsuit carries a failing PFAS grade, and we never recommend buying a failing product.
COS
Women's Asymmetric Double-Faced Swimsuit
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleAzo dyes and colorant chemistry
PossibleFormaldehyde resin finishes
PossibleElastic degradation and residual processing chemicals
Our pick
Patagonia
Women's Bottom Turn Racerback Bikini Top
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleElastane (spandex) degradation under heat or chlorine
Where these two actually differ
- We flag Azo dyes and colorant chemistry, Formaldehyde resin finishes and Elastic degradation and residual processing chemicals on the COS and not on the Patagonia.
- We flag Elastane (spandex) degradation under heat or chlorine on the Patagonia and not on the COS.
- The COS is Polyamide (nylon) blend; double-faced woven textile where the Patagonia is Nylon/polyester blend with elastane (standard swimwear), which is most of the difference in these two grades.
- The gap is 25 points, wide enough that this is not a close call, and the Patagonia is the one to buy.
Both products run through the same public rubric: 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 →
More swimwear: see the full ranking