DMDM Hydantoin

What Is It?

DMDM Hydantoin is a white, crystalline solid. In cosmetics and personal care products, DMDM Hydantoin is used in the formulation of shampoos, hair conditioners, skin care products, moisturizers, bath products, and makeup bases and foundations.

Why Is It Used?

DMDM Hydantoin is a formaldehyde-donor preservative, that prevents or retards microbial growth, thereby protecting cosmetics and personal care products from spoilage.

Follow this link for more information about how preservatives protect cosmetics and personal care products.

Scientific Facts

DMDM Hydantoin is a broad-spectrum antimicrobial agent, effective against fungi, yeast, and bacteria.

Safety Information

The safety of DMDM Hydantoin has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that DMDM Hydantoin was safe as a cosmetic ingredient in the present practices of use. In 2005, the CIR Expert Panel considered available new data on DMDM Hydantoin and reaffirmed the above conclusion.

CIR Safety Review: DMDM Hydantoin is poorly absorbed from the skin. In a laboratory study, oral exposure to DMDM Hydantoin did not result in any adverse effects. The CIR Expert Panel noted that DMDM Hydantoin is a formaldehyde donor in aqueous media. They attributed positive results in some in vitro mutagenicity studies to formaldehyde release. In these studies, the concentrations of DMDM Hydantoin tested were higher than those used in cosmetic and personal care products, likely resulting in much higher concentrations of formaldehyde than found in products. Clinical studies revealed some observations of skin irritation which could also be related to the release of formaldehyde from DMDM Hydantoin.

The CIR Expert Panel has reviewed the safety of formaldehyde in cosmetics and personal care products and concluded that it was safe to a great majority of consumers but has limited the concentration to 0.2% free formaldehyde due to the skin sensitivity of some individuals to this agent. The amount of DMDM Hydantoin required to preserve a product (less than 1%) does not expose the consumer to concentrations of formaldehyde above the 0.2% limit for formaldehyde recommended by the CIR Expert Panel.

DMDM Hydantoin, called Dimethylol, Dimethylhydantoin [1,3-Bis(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione], is listed in Annex VI, Part I (preservatives which cosmetics products may contain) of the Cosmetics Directive of the European Union and may be used in cosmetics and personal care products at a maximum concentration of 0.6%. If the concentration of released formaldehyde exceeds 0.05% in the finished product it must be labeled “contains formaldehyde.”

Link to the EU Cosmetic Regulation:…

More Scientific Information

DMDM Hydantoin is a formaldehyde donor containing up to 2% of the free aldehyde in equilibrium with the hydantoin. In cosmetics and personal care products, it functions as a preservative.