It's the form of Vitamin A they add to it. And 40% of sunscreens add the Vitamin A. SF Chronicle:
Some 40 percent of sunscreens contain retinyl palmitate, including popular brands Coppertone, Banana Boat, Panama Jack, Hawaiian Tropic, and Neutrogena.Here's the study abstract. And more here. (Yes, the story came out a week ago, I didn't see and feel it's important, so there you go.)
