There are so many beauty terms that it can make your head spin. Confused as to what it all means? Our Glam Glossary will help you sort it all out. Follow Allison each week in her quest to decode popular beauty terms, from Alpha Hydroxy Acids to Zinc Oxide.

Zinc Oxide

Products containing zinc oxide

Where you see it: Foundation, eyeshadow, blush, concealer, sunscreen, lip liner, moisturizer, highlighter.

What it is: Zinc oxide, uniquely, the oxide of zinc. Inverted definition aside, it’s an odorless fluffy white powder that results from the oxidation of zinc, a mineral. This oxidation process means that technically zinc oxide is inorganic, because it still had to go through a change from its most natural state, but that doesn’t mean that it’s what we normally think of as a chemical.

What it does: What doesn’t it do? Zinc oxide is used in cosmetics as a bulking agent, a colorant, a skin protectant and a sunscreen agent. (Unlike our old friend oxybenzone, who works to absorb UV radiation, zinc oxide reflects or scatters it.)

Is it safe? According to Skin Deep, zinc oxide has a long history of use in sunscreens and skin care products with “little absorption and no adverse health effects reported.”

Skin Deep’s database also noted that nanoparticles of zinc oxide are also used in some sunscreen formulas, and though there is still no absorption, this form of the ingredient may be potentially toxic if inhaled or in the environment. Nano zinc oxide loses its coloring effect, so sunscreens containing nano zinc oxide do not produce the heavy white coating that others with regular zinc oxide do.

Did you know? Zinc oxide + a very small amount of iron oxides = CALAMINE, which is used in calamine lotion (you know, what you put on chicken pox / mosquito bites when you were little?).

Photo: Hourglass, Mustela, Hampton Sun, Bare Escentuals