Diazolidinyl Urea

What Is It?

Diazolidinyl Urea is a fine white powder. Diazolidinyl Urea can be found in many cosmetic and personal care product types including eye and facial makeup, aftershave, and nail, bath, hair and skin care products.

Why Is It Used?

Diazolidinyl Urea prevents or retards bacterial growth, and thus protects cosmetics and personal care products from spoilage. Follow this link for more information about how preservatives protect cosmetics and personal care products.

Scientific Facts

Diazolidinyl Urea is an effective preservative against bacteria, yeast and molds. This helps to protect the product from inadvertent contamination by the consumer during use. Diazolidinyl Urea works by slowly releasing a small amount of formaldehyde into the formlation.

Safety Information

The safety of Diazolidinyl Urea has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that Diazolidinyl Urea was safe as a cosmetic ingredient up to a maximum concentration of 0.5%.

In 2006, as part of the scheduled re-review of ingredients, the CIR Expert Panel considered available new data on this ingredient and reaffirmed the above conclusion.

CIR Safety Review: The CIR Expert Panel noted that Diazolidinyl Urea was relatively non-toxic in oral subchronic studies. At 5%, Diazolidinyl Urea was not an ocular or skin irritant. In three studies of sensitzation potential, Diazolidinyl Urea was a mild sensitizer, but was not a sensitizer in a fourth study.

Diazolidinyl Urea was nonmutagenic when tested in the bacteria, or in the micronucleus assay. At concentrations up to 0.4%, Diazolidinyl Urea was a mild cumulative skin irritant in humans. It was not a sensitizer in a repeat insult patch test on nonpatient volunteers. Diazolidinyl Urea was not a photosensitizer at 0.25%. The CIR report noted that Diazolidinyl Urea was a formaldehyde releaser. The CIR Expert Panel previously concluded that the use of formaldehyde in cosmetics and personal care products was safe to the great majority of consumers.

The CIR Expert Panel concluded that there was no indication that the use of Diazolidinyl Urea cosmetics and personal care products would release formaldehyde at concentrations which would exceed their previous recommended limits for formaldehyde (0.2%).

Diazolidinyl Urea is listed as N-(Hydroxymethyl)-N-(dihydroxymethyl-1,3-dioxo-2,5-imidazolidinyl-4)-N”-(hydroxymethyl) urea in the Cosmetics Regulation of the European Union (Annex VI, Part I).

Diazolidinyl Urea may be used in cosmetics and personal care products at a maximum authorized concentration of 0.5% and must be labeled “contains formaldehyde” if the concentration of formaldehyde in the finished product exceeds 0.05%.

Link to the EU Cosmetic Regulation: http://europa.eu/legislation_summaries/consumers/product_labelling_and_p…

More Scientific Information

Diazolidinyl Urea is a heterocyclic-substituted urea that functions as a preservative in cosmetics and personal care products. It is manufactured by the reaction of allantoin and formaldehyde.


EU Cosmetic Ingredients Inventory http://ec.europa.eu/consumers/cosmetics/cosing/

Search the FDA Code of Federal Regulations http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm