Chemistry AHA Serum Kosas Deodorant
Low-Medium risk typical cosmetic with no flagged additives.
Kosas' serum and mineral deodorant lack known PFAS-associated ingredients based on public formulation data. Brand makes no PFAS-free claims and does not publicly disclose testing.
We flunk more products than we pass. This one earned its grade. How we grade
Material
water-based serum and mineral deodorant base
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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What Chemistry AHA Serum Kosas Deodorant is made of, ingredients and materials
Kosas Chemistry AHA Serum Deodorant combines a water-based serum base with mineral deodorant actives (typically mineral salts or zinc ricinoleate), avoiding aluminum chlorohydrate and other synthetic antiperspirant compounds. The AHA (alpha hydroxy acid) component is a chemical exfoliant meant to reduce odor-causing bacteria on skin rather than blocking sweat. Water-based formulations in deodorants have lower risk of volatile organic compound off-gassing and cosmetic-grade mineral bases carry minimal toxicity risk when applied topically to underarm skin.
What’s concerning
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.
Fragrance allergens / sensitizers in serum base
No specific fragrance allergen disclosures are available for this product. Serum-based deodorants often include botanical extracts or fragrance compounds; undisclosed fragrance components can trigger contact dermatitis or sensitization in individuals with fragrance reactivity.
Bacterial or mold growth in water-based formulation
Water-based cosmetics require preservative systems to prevent microbial contamination during storage and use. If preservative concentration is insufficient or the product is stored in warm, humid conditions, opportunistic bacteria or mold may proliferate, risking skin infection or irritation.
AHA chemical irritation or photosensitivity
Alpha hydroxy acids are exfoliants that can cause skin sensitization, redness, and peeling, especially at higher concentrations or with frequent use. AHA application to underarm skin (a sensitive area) may increase risk of irritation; AHAs can also increase photosensitivity, though underarm exposure to UV is minimal.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Heavy metals
No recalls or test findings of lead, cadmium, or arsenic contamination in Kosas mineral deodorant formulations are on public record. Cosmetic-grade mineral salts are regulated and typically screened for heavy metal content, but third-party verification is not published for this product.
Source, FDA ↗Talc contamination in mineral base
Kosas does not appear to use talc in this formulation based on available ingredient disclosures. If mineral-based deodorants do include talc, long-term underarm use carries theoretical ovarian cancer risk; this product's water-serum base appears to avoid this concern.
How is this PFAS grade calculated?
The brand's record and disclosure
Kosas is known for emphasizing clean beauty and transparent ingredient labeling, though the brand makes no explicit public commitment to PFAS avoidance. The company has not faced established recalls or safety controversies tied to this product line. No third-party certifications (like EWG Verified or Clean Beauty Certified) are listed on public record for this specific deodorant, meaning safety relies on ingredient transparency and cosmetic regulatory compliance rather than independent audit.
How it compares in its category
This product positions itself in the premium natural/mineral deodorant segment, which typically avoids aluminum antiperspirants and synthetic fragrance loads. Compared to conventional antiperspirant deodorants, mineral bases carry lower risk of skin irritation and systemic aluminum absorption. The AHA addition is less common in deodorants and may offer modest odor control benefits, though efficacy data from controlled trials is not widely published; it sits between purely natural options and clinical-strength synthetics in performance and safety profile.
If you buy it
Patch test on a small underarm area first, as AHA exfoliants can irritate sensitive or freshly shaved skin. Store in a cool, dry place to maintain the serum consistency and prevent bacterial growth in the water base. Replace every 12 months or if you notice color change, separation, or odor indicating microbial contamination. Reapply as needed for odor control; mineral deodorants typically require more frequent reapplication than antiperspirants since they do not block sweat.
What is not known about PFAS in this product?
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Kosas has made none
Formulations change between production runs, so check the current label. How we grade.
What are the PFAS-free alternatives to Chemistry AHA Serum Kosas Deodorant?
- mineral-based powder blend (arrowroot, magnesium hydroxide, mica)
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- Skin irritation from magnesium hydroxide alkalinity
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- A third party reports verifying it as PFAS-free
- Fragrance allergens (natural essential oils)
2 hazards checked on this product, all on its full breakdown.
- natural mineral powders, plant-based actives, beeswax
- We found no PFAS statement from the brand
- Beeswax purity and contamination
2 hazards checked on this product, all on its full breakdown.
More deodorant 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.