9 Sneaky Ingredients to Watch Out for in Skin Care Products

It's not just a tongue twister, methylisothiazolinone is a common skin care ingredient that can cause allergic reactions in many skin types. "MI is a preservative used to prevent bacterial overgrowth in cosmetics and household products, such as make-up remover wipes, shampoos, deodorants, detergents, moisturizers, make-up, and baby wipes," says Dr. Birnbaum. "It is one of the most common ingredients to cause allergic contact dermatitis."

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