What it is
Imidazolidinyl Urea is a white powder.
What it does
Imidazolidinyl Urea is a preservative that kills and prevents the growth of bacteria in cosmetics, thus making them last longer. It doesn’t offer much protection against fungi though and because of it, it is usually used with other preservatives such as parabens. Imidazolidinyl Urea works by releasing formaldehyde. Although formaldehyde is toxic, it is released only in minuscule amounts that don’t pose a threat to human health.
Imidazolidinyl Urea can cause contact dermatitis in some people.
In the European Union this ingredient can be used only in concentrations up to 0.6%, while in Japan only in rinse-off products and at a maximum concentration of 0.3%. In addition, some experts also recommend to avoid this ingredients in products for infants.