The 10 Worst Things You Can Put on Your Face, According to a Cosmetic Chemist

Where they're commonly found: face creams, body lotions, mascaras, shampoos, conditioners, hairstyling products, antiperspirants, shaving products

What they do: Parabens, which can be identified in ingredient labels by sussing out prefixes such

as methyl-, propyl-, butyl-, ethyl-, and isobutyl- with the suffix paraben, are preservatives. "They protect cosmetics from dirt and function as a preservative to help increase the shelf life of products," Walch explains.

Why steer clear: You've likely been accosted with directives to avoid parabens before now, but do you know why? According to Walch, parabens can cause allergic skin reactions, redness, itching, and even damage to the hormonal system. "There's usually only a small percentage present in a product, but according to some studies, with long-term use, it accumulates in the body, where it can affect the hormonal system," she says. Worst case, as Robinson told me, they can potentially be carcinogenic or cancer causing.

Possible replacements: benzoic or sorbic acids