Medium-Flow Leakproof Period Underwear vs Basic Mid-Rise Period Brief: which is safer?
Modibodi Basic Mid-Rise Period Brief is the clear pick. Knix Medium-Flow Leakproof Period Underwear carries a failing PFAS grade, and we never recommend buying a failing product.
Knix
Medium-Flow Leakproof Period Underwear
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleUndisclosed waterproof coating chemistry
PossibleSkin sensitization from dyes or finishes
PossibleCoating degradation and leachables over time
Our pick
Modibodi
Basic Mid-Rise Period Brief
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleWater-resistant coating degradation
PossibleMicrobial growth and odor with improper care
Where these two actually differ
- We flag Undisclosed waterproof coating chemistry, Skin sensitization from dyes or finishes and Coating degradation and leachables over time on the Knix and not on the Modibodi.
- We flag Water-resistant coating degradation and Microbial growth and odor with improper care on the Modibodi and not on the Knix.
- The Knix is Organic cotton/viscose with proprietary waterproof coating (unspecified) where the Modibodi is organic cotton blend with water-resistant coating, which is most of the difference in these two grades.
- The gap is 75 points, wide enough that this is not a close call, and the Modibodi is the one to buy.
- We are less certain about the Knix grade, at 42% confidence against 85%, because it discloses less.
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 period underwear: see the full ranking