Alcohols
Alcohols are very drying and irritating solvents made from propylene, a petroleum derivative. They are very irritating and drying because they can strip the skin’s natural acid mantle which dehydrates the cells and makes the body more vulnerable to bacteria and viruses. A significant amount of research has shown that alcohol may cause free-radical damage to the skin including brown spots, hyperpigmentation and premature aging.
Check product labels for isopropyl alcohol, SD alcohol 40 and ethyl alcohol, ethanol, denatured alcohol, methanol and benzyl alcohol.
Urea
Urea is one of nature’s best sources of nitrogen, found in and produced by most plants and animals. In fact, urea is found in the top layers of healthy skin as an active part of the moisture barrier. The problem lies with manmade urea; as a near skin-identical compound, synthetic urea quickly moves through the natural barrier of the skin and allows the other chemicals in the product to move in to the body with it. The American Academy of Dermatology reports that urea is a primary cause of contact dermatitis, especially in concentrated amounts found in skin exfoliates and fertilizer. It also contains small amounts of formaldehyde, a carcinogenic chemical that is toxic when inhaled.
Urea can be labeled as diazolidinyl urea, imidazolidinyl urea and DMDM hydantoin.