Kosas Chemistry AHA Serum Deodorant Fragrance Free
Liquid cosmetic serum, inherently lower PFAS concern.
Kosas AHA serum is a liquid cosmetic product without waterproofing or stain-resistant treatments typical of PFAS-containing items. No public PFAS disclosures or certifications found; brand is silent on the topic.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Liquid serum with AHA active ingredients, typical cosmetic base
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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What Kosas Chemistry AHA Serum Fragrance Free is made of, ingredients and materials
Kosas Chemistry AHA Serum is a liquid cosmetic base formulated with alpha hydroxy acids (typically glycolic or lactic acid) as active exfoliating agents. Liquid serums inherently carry lower contamination and degradation risks than solid or powder forms because they lack particulate fillers and are typically preserved with common cosmetic preservatives rather than prone to surface oxidation. The fragrance-free formulation eliminates synthetic fragrance allergens and volatile organic compounds commonly associated with scented personal care products. AHA actives themselves are well-established cosmetic ingredients with decades of safety history, though they do increase skin sensitivity and require sun protection.
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.
1,4-dioxane (preservative byproduct)
Liquid cosmetics may contain trace 1,4-dioxane as a byproduct of ethoxylated preservatives or emulsifiers. Kosas does not publish data on 1,4-dioxane screening. At typical cosmetic exposure levels this is considered a low acute risk but a regulated impurity in the EU; absence of testing does not confirm absence.
Skin sensitization from AHA actives
AHAs are documented to increase skin irritation, erythema, and photosensitivity when used incorrectly or in sensitive populations. This is a use-dependent hazard, not a manufacturing defect; proper dilution, frequency, and sun protection mitigate risk significantly. Fragrance-free formulation reduces additional irritant and allergenic load.
Microbial contamination if seal compromised
Liquid serums with water-based formulas and modest preservative systems are vulnerable to bacterial or fungal growth if the container is opened, contaminated, or stored improperly. Kosas does not publish data on preservative efficacy testing (challenge testing per USP 51). Inspect for cloudiness, separation, or odor before use.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Formaldehyde / VOCs
No public record or ingredient list indicates use of formaldehyde-releasing preservatives (e.g., DMDM hydantoin, diazolidinyl urea) in Kosas Chemistry products. Most indie clean beauty brands avoid these in favor of alternatives like phenoxyethanol or preservative complexes that present lower concern for certain contaminant pathways.
Source, ATSDR ↗Heavy metals
This product is fragrance-free and appears to be colorless or near-colorless, which typically excludes iron oxides, ultramarines, or other mineral pigments prone to lead/cadmium contamination. No public record of heavy metal contamination in Kosas products.
Source, FDA ↗How is this PFAS grade calculated?
The brand's record and disclosure
Kosas is a clean beauty brand marketed toward ingredient transparency, though like many indie brands it does not publish comprehensive third-party safety certifications (e.g., no NSF, EWG Verified, or Cradle to Cradle marks on record). The brand has no documented safety recalls or major contamination incidents in public databases. Ingredient disclosure on their website is relatively transparent for a cosmetics line, but the company has not issued formal statements on heavy metal testing, 1,4-dioxane screening, or formaldehyde releasers, which is typical of smaller brands without mandatory disclosure laws in those categories.
How it compares in its category
AHA serums typically have lower concern for certain contaminants because they are water-based liquids without talc, bismuth oxychloride, or particle-based pigments that often carry heavy metal contaminants. Fragrance-free versions avoid the allergen and sensitization profile of scented serums. Compared to powder exfoliants, creams, or foundation products, liquid AHA serums have simpler formulas and fewer opportunities for manufacturing defects or cross-contamination. The main trade-off is higher potency of AHA actives, which increases skin irritation risk if misused rather than product safety per se.
If you buy it
Apply only to clean, dry skin at night and always use SPF 30+ the following day, as AHAs increase UV photosensitivity. Start with 2-3 applications per week to assess tolerance; do not exceed daily use unless advised by a dermatologist. Discontinue if redness, burning, or barrier damage occurs. Store in a cool, dark place away from direct sunlight to preserve AHA potency and prevent oxidative degradation of the base formula. Replace if the product develops an off-odor, cloudiness, or separation, which may indicate microbial contamination or preservative failure.
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 Kosas Chemistry AHA Serum Deodorant Fragrance Free?
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- Skin irritation from magnesium hydroxide alkalinity
- cosmetic formulations, primary ingredients listed
- 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.