Imidazolidinyl Urea

What Is It?

Imidazolidinyl Urea is an odorless white powder. In cosmetics and personal care products, Imidazolidinyl Urea can be found in many product types including lotions, creams, hair conditioners, shampoos and deodorants.

Why is it used in cosmetics and personal care products?

Imidazolidinyl Urea kills microorganisms, or prevents or inhibits their growth and reproduction. Preventing the growth of microbes protects cosmetics and personal care products from spoiling. Follow this link for more information about how preservatives protect cosmetics and personal care products.

Scientific Facts:

Imidazolidinyl Urea is one of the most frequently used preservatives in cosmetics and personal care products. It acts synergistically with other preservatives resulting in a system that gives a wider range of protection against microorganisms.

Safety Information:

The safety of Imidazolidinyl Urea has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel.

The CIR Expert Panel evaluated the scientific data and concluded that Imidazolidinyl Urea was safe for use in cosmetics and personal care products. In 2001, the CIR Expert Panel considered available new data on Imidazolidinyl Urea and reaffirmed the above conclusion.

More safety Information:

CIR Safety Review: In its review the CIR Expert Panel indicated that Imidazolidinyl Urea had low acute and subchronic toxicity, it did not produce developmental effects, it produced little or no eye or skin irritation, and it was not phototoxic. It was considered a weak sensitizer, although a repeat insult patch test in 200 subjects showed no sensitzation or irritation.

Based on the available information, the CIR Expert Panel concluded that Imidazolidinyl Urea was safe for use in cosmetics and personal care products.

Imidazolidinyl Urea is listed in Annex VI, Part 1 (preservative which cosmetic products may contain) 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 0.05%.

Link to the EU Cosmetic Regulation:…

More informtion about formaldehyde.

More Scientific Information:

Imidazolidinyl Urea is a heterocyclic substituted urea that functions as a preservative in cosmetics and personal care products.

Imidazolindinyl Urea is a formaldehyde-releasing preservative. However, there are only trace amounts of free formaldhyde in finished products.

Preservatives are ingredients which prevent or retard microbial growth and thus protect cosmetic products from spoilage.

The use of preservatives is required to prevent product damage caused by microorganisms and to protect the product from inadvertent contamination by the consumer during use. The use of more than one preservative can sometimes increase efficacy due to synergism.


The New Zealand Dermatological Society Inc.

EU Cosmetics Inventory

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