U by Kotex Ultra Thin Pads
Waterproof coating unspecified; PFAS risk unclear without disclosure.
U by Kotex does not publicly disclose PFAS status or waterproof treatment chemicals. Period pad backsheets typically use water-resistant coatings that may contain PFAS, though specifics remain undisclosed.
The better-graded swap
Seventh Generation
Seventh Generation Chlorine Free Maxi 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/rayon with proprietary absorbent core and waterproof barrier
Lab data
No public lab test
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What U by Kotex Ultra Thin Pads is made of, ingredients and materials
U by Kotex Ultra Thin uses cellulose and rayon as the absorbent matrix with a proprietary synthetic core and an unidentified waterproof barrier layer. Rayon (viscose) is processed from wood pulp using chemical solvents and is not inherently problematic, but the waterproof coating composition is not public, which is the main concern here. The absorbent core formulation is proprietary and not disclosed on the package or brand website, meaning potential additives (softeners, surfactants, antimicrobials) cannot be assessed.
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.
Waterproof barrier coating (unspecified chemistry)
The barrier material and its components are not disclosed. Modern waterproof pads typically use polyurethane, polypropylene, or coated films; some may contain fluorinated compounds (PFAS) to enhance water resistance, but Kotex has not clarified this or ruled it out.
Skin sensitization from undisclosed additives
Period pads often include lotion, fragrance, or antimicrobial compounds not listed on packaging. U by Kotex Ultra Thin advertises softness but does not itemize what creates that property; individuals with contact dermatitis or fragrance sensitivity may react, though no product-specific incident cluster is on record.
What’s reassuring
Rayon processing residues and additives
Rayon/viscose production involves sodium hydroxide and carbon disulfide solvents, but final fiber is chemically inert. U by Kotex does not disclose whether softeners, surfactants, or antimicrobial agents are present in the absorbent core, so trace residuals cannot be ruled in or out.
Bleach residues in cellulose
Cellulose pulp is typically bleached during production. No testing has established clinically relevant bleach residues in finished pads from this brand or category, but processing is not disclosed by Kotex.
Microplastic or synthetic fiber shedding
The core and barrier use synthetic or semi-synthetic materials, but no studies have documented shedding of microplastics from period pads in normal use. This remains an unevaluated environmental and internal exposure pathway specific to modern pad design.
How is this PFAS grade calculated?
The brand's record and disclosure
Kotex (Kimberly-Clark) does not publish ingredient lists or material transparency reports for this product line. The brand has not publicly committed to PFAS avoidance or third-party testing for period products. No published recalls or safety incidents specific to this product are on record in FDA or safety databases. The lack of disclosure on the waterproof barrier, a key component in modern pads, reflects an industry-wide gap rather than a unique Kotex failing, but it prevents independent verification of chemical hazards.
How it compares in its category
Most conventional period pads (Tampax, Always, Kotex) do not disclose waterproof coating materials; this is standard practice across mass-market brands. Certified organic or plastic-free alternatives (Cora, Rael, Aunt Flow) typically publish ingredient lists and avoid synthetic waterproof layers, using cotton or wool. U by Kotex Ultra Thin sits in the mainstream undisclosed segment; it is not exceptional in transparency but also carries no documented recalls or health complaints more frequent than category norms.
If you buy it
Store pads in a cool, dry place away from heat or humidity to prevent degradation of the absorbent core and barrier. Replace the pad after 4-8 hours of use depending on flow; leaving it in place longer can increase bacterial colonization risk, independent of material. Do not expose pads to direct flame or high heat. If you experience persistent irritation, itching, or rash after switching brands, consider that rayon or undisclosed additives in the core may be contributors; patch-test with a single pad and track timing.
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
- Kotex has made a specific claim
Formulations change between production runs, so check the current label. How we grade.
What are the PFAS-free alternatives to U by Kotex Ultra Thin Pads?
- organic cotton, wood pulp
- The brand calls it PFAS-free, which we have not verified
- Fragrance allergen content
- cellulose, cotton blend, absorbent core
- We found no PFAS statement from the brand
- Bleach residues and processing chemicals in cellulose
3 hazards checked on this product, all on its full breakdown.
- Cotton, wood pulp absorbent core, plastic backing
- Pesticide residue
2 hazards checked on this product, all on its full breakdown.
More period pads grades
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.