Consumer Reports warns against do-it-yourself sunscreen

NEW YORK (WABC) -- Between Pinterest and Instagram and crafting competitions, everyone seems to be looking to DIY these days. But Consumer Reports warns, one thing you should not try to make at home is sunscreen.

A quick search on the internet and you'll be swimming in recipes and how-to videos -- not for whipping up food -- but for whipping up sunscreen. These sites may claim to have the formula for sun protection, but dermatologist Dr. Jessica Krant says it could actually be a recipe for something a lot worse.

"You're at risk for sunburn in the short term," she said. "But in the long term, you're really at risk for skin cancer."

That's in part because there's no way for you to test the effectiveness of the mixture.

"You have no quality control," Consumer Reports health editor Trisha Cavlo said. "You can't determine what the SPF of the product is. You don't even know if those ingredients have any kind of SPF protection."

Take zinc oxide, one of the potential ingredients in homemade sunscreen. The mineral protects skin by deflecting the sun's UV rays rather than absorbing them the way chemical-based sunscreens do.

"In CR tests of store-bought sunscreens, the ones that contain zinc oxide or titanium dioxide or both as active ingredients have been consistently found to be less effective than those that contain the chemical active ingredients," Calvo said.

And effectiveness is key.

"In childhood, one single blistering sunburn can increase the risk of skin cancer by 50 percent," Dr. Krant said.

To minimize harmful sun exposure, Dr. Krant says you should not only use sunscreen -- and use it correctly -- but also apply a little strategy when heading outdoors.

"The best protection is to avoid strong midday sun and plan most of your activities early or later in the day," she said. "And to wear sun protective fabric and sun protective clothing, hats and sunglasses in addition to your sunscreen."