U by Kotex Ultra Thin Overnight Pads with Wings, Extra Heavy Absorbency
Skip until brand discloses waterproof layer chemistry; PFAS risk unclear.
Overnight pads require waterproof backing, but Kotex does not disclose the coating used. Standard industry practice often involves PFAS-based water repellents in menstrual products; independent testing is unavailable.
The better-graded swap
Aunt Flow
Aunt Flow Pads
100/100 safety
Same rubric that flunked this product. The swap earned Excellent.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Cellulose/wood pulp core with plastic backing and absorbent polymers; waterproof layer composition unspecified
Lab data
No public lab test
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What U by Kotex Ultra Thin Heavy Absorbency is made of, ingredients and materials
U by Kotex Ultra Thin Overnight uses a cellulose/wood pulp absorbent core, a plastic backing layer, and absorbent polymer gels (likely superabsorbent polymer, SAP, typically sodium polyacrylate). The waterproof layer composition is not disclosed by the brand. Cellulose and SAP are inert under normal use; the concern centers on the waterproof backing, which may contain PFAS or other synthetic chemicals to achieve water resistance, but this remains unconfirmed.
What’s concerning
Waterproof / stain-resistant treatment
Water-repellent coating treatments have historically used PFAS.
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
PFAS
Waterproof layer chemistry is not disclosed by the brand. Fluorinated polymers (PFCs/PFAS) are common in menstrual-pad backings for water resistance; no third-party testing or PFAS-free certification is on record for this product.
Source, ATSDR ↗What’s reassuring
Dioxins and other residuals from bleaching
Cellulose pulp used in pads is typically bleached; modern pulp mills employ chlorine-free or elemental-chlorine-free (ECF) processes that minimize dioxin formation. No dioxin contamination has been reported in Kotex products or the ultra-thin category.
Allergens in fragrance or additives
U by Kotex Ultra Thin Overnight is unscented (no fragrance added). No fragrance allergens or contact sensitizers are reported. Cellulose, SAP, and plastic backing are not known allergens in non-sensitized users.
Microplastics
The plastic backing is a laminated sheet, not a loose material; under normal vaginal use, it does not fragment or shed microplastics. No reports of plastic particle shedding or vaginal microplastic contamination from this product exist.
Source, EPA ↗Absorbent polymer (SAP) exposure
Superabsorbent polymers in menstrual products are internally regulated and do not leach into vaginal tissue under normal use. No systemic or local toxicity from SAP has been reported in menstrual-pad users over decades of use.
How is this PFAS grade calculated?
The brand's record and disclosure
Kotex/U by Kotex does not publicly disclose full ingredient lists or material chemistry for menstrual products, including waterproof layer composition or PFAS testing. The brand has not published third-party certifications (e.g., standard for restricted substances in textiles) or voluntary PFAS avoidance commitments. This silence is common in the menstrual-product industry but leaves the waterproof layer's chemistry opaque to consumers.
How it compares in its category
Most mass-market overnight pads (Kotex, Tampax, Always) use undisclosed waterproof backings; few brands voluntarily test for PFAS or publish material specs. Organic or eco-certified brands (e.g., Seventh Generation, Natracare) often disclose materials and avoid fluorinated polymers, but U by Kotex Ultra Thin sits in the conventional, non-transparent segment. Overnight thickness and absorbency in this category typically trade off reduced breathability for PFAS or other synthetic waterproofing.
If you buy it
Store in a dry place; cellulose and SAP do not degrade with normal handling. No heat exposure during use or storage is required or relevant. Replace every 4-8 hours as directed; do not reuse. If you experience vaginal irritation, rash, or allergic symptoms, discontinue and consider a brand with disclosed materials. Given PFAS uncertainty, users concerned about fluorinated compound exposure may prefer brands with published waterproof-layer chemistry or organic certifications.
What is not known about PFAS in this product?
- Basis
- Model estimate, 45% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- U by Kotex has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
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25Cora Free To Flow Period UnderwearCompare vs Natracare →All period care →How we score, every product runs through the same public 0-100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.