DMDM Hydantoin
Also known as: 1,3-Bis(hydroxymethyl)-5,5-dimethylhydantoin, Glydant
Last updated:
DMDM Hydantoin is a formaldehyde-releasing preservative permitted in the EU at up to 0.6% (Annex V #33) and in the US without specific concentration limits. As a formaldehyde donor, it hydrolyzes in solution to release small amounts of free formaldehyde that provide preservation. Increasing regulatory and consumer pressure on formaldehyde donors has led many brands to reformulate.
Regulatory status by market
| Market | Status | Detail | Source |
|---|---|---|---|
| European Union | Restricted | Max 0.6%; labeling required if free formaldehyde >0.05% | Annex V #33 |
| United Kingdom | Restricted | Max 0.6% (mirrors EU) | UK Cosmetics Regulation |
| United States | Permitted | No federal limit; CIR-recommended max 0.6% | CIR review |
| Canada | Restricted | On Hotlist with concentration limits | Health Canada Hotlist |
Safety profile
DMDM Hydantoin is associated with contact allergic reactions, particularly in individuals already sensitized to formaldehyde. Lawsuits in the US have alleged hair-loss claims linked to DMDM Hydantoin shampoos, though causation has not been established. The EU requires products containing DMDM Hydantoin to be labeled with the phrase 'releases formaldehyde' when free formaldehyde exceeds 0.05%.
Common uses
- Preservation in shampoos and conditioners
- Preservation in body washes and liquid soaps
- Replaced parabens in some legacy formulations
Primary sources
Regulatory status is current to the "Last updated" date above. Always verify against the regulator's authoritative publication for the specific market and product category before relying on this summary for compliance decisions.
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