We all know that sunscreen is a tool to protect our skin against a host of ailments, including cancer and premature aging, but according to the Environmental Working Group, vitamin A derivatives retinol and retinyl palmitate, which are a popular additive in antiaging sunscreens, could speed the development of tumors when used on skin that's being exposed to the sun.

It's pretty common knowledge that vitamin A increases skin's sensitivity to light — anyone who's ever used Retin-A or Accutane gets a warning from their doctor about avoiding sun when they get their prescription — so this isn't surprising. It's the fact that vitamin A is being put into sunscreen in the first place that's weird. Why put a photosensitizing agent into a product people are buying expressly as sun protection?

I know that some people are going to blow this off as an "everything gives you cancer" story, but they shouldn't. The takeaway is really about connecting the dots, and finding out what's in the products you use. Do you use sunscreen that contains this vitamin, and if so, would finding out it had vitamin A in it make you think about changing brands?