Is Imidazolidinyl Urea Harmful to the Skin?

In our daily lives, when caring for our skin, we often use facial masks or skincare products. However, if these products are not produced by reputable manufacturers, they may contain excessive amounts of heavy metals or preservatives, which can lead to skin discoloration or ulceration. Imidazolidinyurea is a preservative commonly found in cosmetics and can be harmful to the skin. Therefore, when selecting cosmetics, it is crucial to purchase them through formal channels.

Imidazolidinyurea is a chemical compound with the English name "Imidazolidinyurea" and CAS number 39236-46-9. Its molecular formula is C11H16N8O8 and molecular weight is 388.29400. Its exact mass is 388.10900, and PSA is 221.54000. This compound appears as a white fluid powder with a faint characteristic odor. It has a density of 1.85g/cm3 and a refractive index of 1.714. It is soluble in water and is stable. The recommended storage condition is 2-8ºC.

1. Imidazolidinyurea can be used in creams, shampoos, lotions, and conditioning agents. It can be used alone or combined with parabens or IPBC to enhance its preservative effect. The pH range for its use is 3-9, with a typical addition amount of 0.2%-0.4%. The maximum allowed addition amount is 0.6%, and it can be added within a wide temperature range (<90℃).

2. It is often used in combination with parabens or Kathon CG as a preservative in cosmetics. It can be used in creams, lotions, shampoos, etc., and is especially suitable for high-grade nutritional cosmetics that are prone to copper-green Pseudomonas aeruginosa contamination when the pH value is alkaline. The typical usage amount is 0.1%-0.5%.

Imidazolidinyurea-based preservatives, including bis(hydroxymethyl)imidazolidinyurea (Diazolidinyl urea) and DMDM hydantoin, have been used for many years, and the production technology of various brands is relatively mature. However, due to their ability to release formaldehyde, they can be irritating to the skin. Therefore, these two preservatives are currently widely used in rinse-off cosmetics such as cleansers, and many older formulas use them in combination with parabens as preservatives.