Urea isn't the most exciting or ... enticing topic. But it's a fairly common beauty ingredient, and I've long wondered what its benefits (and not-so-beneficial properties) were, and what it's doing in our skincare products.

If you've taken any chemistry class, you'll know that urea is the main component of urine in mammals. The Naked Chemist says that urea is naturally occurring in our skin's tissue and makes up 7% of our natural moisturization, and in cosmetics serves to maintain a balance in our skin's moisture by drawing skin from the atmosphere (a humectant) and creating a barrier that prevents our skin from losing moisture. And because of its chemical make-up, urea serves as an exfoliant. Supposedly, urea also acts as a preservative.

According to Good Guide, urea has been banned in cosmetics in Canada. It's widely agreed that the most common side effect of using products that contain urea is skin inflammation or irritation, though it is also said to be able to release formaldehyde, which is a carcinogen. According to Truth In Aging, the specific types of urea that are said to release formaldehyde are diazolidinyl urea and imidazolidinyl urea (Germall 115), so it's best to avoid those.

Urea on the whole is pretty difficult to avoid in skincare, be it natural/organic products or not. But at the moment, unless you have extremely sensitive skin, urea seems mostly safe -- barring diazolidinyl and imidazolidinyl ureas. EWG.org has a wonderfully simple guide to ingredients you should avoid in your beauty products, including imidazolidinyl urea, if you're concerned.

Photo: Allure.com