O.b Pro Comfort Super Plus 16 pad vs Cotton Overnight Set Period Underwear: which is safer?

O.b Pro Comfort Super Plus 16 pad is the clear pick. Thinx Cotton Overnight Set Period Underwear carries a failing PFAS grade, and we never recommend buying a failing product.

Our pick

O.b Pro Comfort Super Plus 16 pad

OB

O.b Pro Comfort Super Plus 16 pad

PFAS grade

Good 70/100

Overall grade

Good 52/100

Verdict

Buy

Hazard flags

⚑ 3

Material

rayon/viscose, cotton, and gelling polymers

Confidence

78%

PossibleMicroplastic shedding or degradation

ReportedIrritation or allergic sensitization from adhesive or synthetic fibers

PossibleBacterial growth or contamination from prolonged moisture

Thinx Cotton Overnight Set Period Underwear

Thinx

Cotton Overnight Set Period Underwear

PFAS grade

Poor 25/100

Overall grade

Bad 0/100

Verdict

Skip

Hazard flags

⚑ 4

Material

Cotton with water-resistant membrane/lining layer (composition unspecified)

Confidence

45%

LikelyUndisclosed waterproofing agent (likely PFAS-based)

PossibleFormaldehyde resin finishes

PossibleMembrane degradation and microplastic shedding

Where these two actually differ

  • We flag Microplastic shedding or degradation, Irritation or allergic sensitization from adhesive or synthetic fibers and Bacterial growth or contamination from prolonged moisture on the OB and not on the Thinx.
  • We flag Undisclosed waterproofing agent (likely PFAS-based), Formaldehyde resin finishes, Membrane degradation and microplastic shedding and Allergic contact dermatitis from undisclosed additives on the Thinx and not on the OB.
  • The OB is rayon/viscose, cotton, and gelling polymers where the Thinx is Cotton with water-resistant membrane/lining layer (composition unspecified), 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 OB is the one to buy.
  • We are less certain about the Thinx grade, at 45% confidence against 78%, 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 pads: see the full ranking