DMDM Hydantoin
1,3-Bis(hydroxymethyl)-5,5-dimethylhydantoin
What it is
A formaldehyde-releasing preservative (CAS 6440-58-4) that slowly releases formaldehyde in aqueous formulations to inhibit microbial growth. One of several formaldehyde-donor preservatives used across the industry.
In this product: Antimicrobial preservative, releases formaldehyde over time to prevent bacterial and mold growth in water-based formulas.
Dose & route, what actually matters
Dermal, leave-on application across large body surface area. Released formaldehyde can be absorbed through skin or volatilized and inhaled during application. Body lotion represents higher surface-area exposure than a facial product.
EUROPEAN UNION
EU Commission Regulation (EU) 2022/1181 (July 2022) lowered the mandatory ‘releases formaldehyde’ label warning trigger from 0.05% (500 ppm) to 0.001% (10 ppm) released formaldehyde, a 50× tightening. Products must comply by July 31, 2024 for market placement; July 31, 2026 for sale. No ban; full disclosure and labeling required.
UNITED STATES
No concentration limit or mandatory warning label for DMDM Hydantoin in cosmetics. CIR Expert Panel concluded ‘safe as used’ (1988, reaffirmed 2008). No US equivalent to the EU 10 ppm warning threshold.
The evidence
EU Commission Regulation (EU) 2022/1181 (July 8, 2022) lowered the mandatory ‘releases formaldehyde’ label warning threshold from 500 ppm to 10 ppm, a 50× tightening. Products not relabeled cannot be placed on the EU market after July 31, 2024.
regulatory · 2022 · source
IARC Monograph Volume 100F (2012): Formaldehyde classified Group 1, carcinogenic to humans, based on nasopharyngeal cancer and leukemia evidence from occupationally exposed workers.
regulatory · 2012 · source
California Prop 65: Formaldehyde (the released substance) is listed on California Prop 65 as a known carcinogen. The listing applies to free formaldehyde; formaldehyde releasers are not separately listed but release the listed substance.
How to avoid it
Check labels for DMDM Hydantoin, as well as other formaldehyde releasers (Quaternium-15, Diazolidinyl Urea, Imidazolidinyl Urea, Bronopol). Fragrance-free, paraben-free lotions are often reformulated to also omit formaldehyde releasers.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.