Expert Panel for Cosmetic Ingredient Safety

The safety of imidazolidinyl urea has been assessed by the Expert Panel for Cosmetic Ingredient Safety (Expert Panel) on several occasions. In 1980, the Expert Panel evaluated the scientific data and concluded that imidazolidinyl urea was safe when incorporated in cosmetics products in amounts similar to those presently marketed. The Expert Panel reviewed imidazolidinyl urea again in 2001 and 2019 and determined that no new relevant data would require a re-review of this ingredient. Therefore, the Expert Panel reaffirmed the original ‘safe as used’ conclusion.

In the 1980 CIR review, the Expert Panel indicated that imidazolidinyl urea had low acute and subchronic toxicity, did not produce developmental effects, caused little or no eye or skin irritation and was not phototoxic. Laboratory studies indicated it was considered a weak skin sensitizer (i.e., allergic skin reactions); however, a clinical patch test in 200 human subjects showed no sensitization or irritation. Based on the available information, the Expert Panel concluded that imidazolidinyl urea was safe for use in cosmetics and personal care products.

Imidazolidinyl urea is listed in Annex V, entry 27 (the list of preservatives allowed in cosmetics products) of the Cosmetics Regulation of the European Union. It may be used at a maximum concentration of 0.6% in cosmetics and personal care products and must carry a warning “contains formaldehyde” if the concentration of formaldehyde in the finished product exceeds 0.001%.