Chances are that your plans for this summer call for plenty of outdoor time—which means they should also call for plenty of sunscreen. But if you’re considering whipping up some homemade sunscreen while you’re prepping potato salad for your cookout or picnic, you should think again.

Search for “DIY sunscreen recipes” on Google or Pinterest and you’ll get more than 800,000 hits. Along with step-by-step instructions, some of the posters providing these how-tos also offer their opinions on why you’d be better off skipping store-bought sunscreen. They raise concerns about the chemicals in commercial sunscreens being toxic and prices being too high, and they make claims that homemade “all-natural” alternatives are better and safer. 

Several of the recipes call for zinc oxide, a mineral that protects skin by deflecting the sun’s UV rays (as opposed to chemical sunscreen ingredients that work by absorbing those rays), along with a mix of shea butter and various oils. Some are just a mix of essential oils. Some are just a mix of shea butter and/or coconut oil with essential oils, such as carrot seed oil or red raspberry oil. Different bloggers make unsubstantiated SPF claims, saying their concoctions provide a SPF 20, 50, or 80, for instance.

More on Sunscreens

“Some people worry about the safety of chemical ingredients in commercial sunscreens, but the active ingredients used in this country have been cleared by the Food and Drug Administration,” says Joel L. Cohen, M.D., an associate clinical professor of dermatology at the University of Colorado and director of AboutSkin Dermatology in Denver. “What’s unsafe is making homemade sunscreen using ingredients without proven SPF or broad spectrum coverage in formulations that aren’t standardized or verified for their efficacy. That can leave you unprotected from the sun—a known carcinogen.”

Consumer Reports does an annual review of sunscreens—including performance and price. The mineral (sometimes called natural) sunscreens included in CR's tests were more likely to receive low ratings for performance compared with sunscreens that contain chemical active ingredients. As to the concern of cost, an effective sunscreen doesn’t have to break the bank. Pure Sun Defense SPF 50, a CR Best Buy, costs just 75 cents per ounce—not much more than you’ll spend on ingredients for homemade sunscreen.

But the biggest reason not to whip up your own batch is that anything you read about homemade sunscreen online is based on anecdotal information, not actual research.  “Do you really want to experiment on yourself or your child and see if you get burned?” asks Cohen. “One blistering sunburn translates into a 50 percent increased risk of skin cancer. The public needs to be aware that some are very high-risk skin cancers, and one person in this country dies every hour from a melanoma.”