Although you should be wearing an SPF every day, in the summer you need a more intense sunscreen for days at the beach, long bike rides and other summer fun. Unfortunately, while you need sunscreen to keep your skin healthy, some sunscreens themselves are not so healthy. That's because certain chemicals used to block the rays can impact our bodies in negative ways. The Environmental Working Group has taken a lead in educating the public about some of those common chemicals that can do harm, not good. Here’s a run-down on things to look out for when you’re buying sunscreen. 1. Avoid oxybenzone and octinoxate These common sunscreen ingredients absorb UV rays, but some research shows that the chemicals are absorbed into the body where they act as hormone disruptors. These chemicals can mimic hormones like estrogen and have been associated with reproductive and thyroid issues in animals. Instead of a chemical sunscreen, you might want to look for a mineral sunscreen, which uses zinc oxide and titanium dioxide to physically block the sun’s rays. 2. Avoid retinyl palmitate and other forms of retinol Retinyl palmitate is a form of vitamin A. While vitamin A is an antioxidant that can help slow the aging process in skin, using vitamin A on your skin also makes you more sensitive to the effects of sunlight, so it's best not to use it outdoors during the day. And according to a U.S. government study, retinyl palmitate may actually speed the growth of skin tumours, making it dangerous for anyone at risk of skin cancer. 3. Look for broad spectrum coverage You might buy an SPF 50 sunscreen thinking you’re doing a great job protecting your skin, but unless you get a broad spectrum sunscreen, you’re only protected against UVB rays, not UVA. While sunscreens traditionally protect against the UVB rays that cause burns, many can leave you unprotected from the UVA rays that penetrate deeper and damage skin cells and their DNA, which can lead to aging and cancer. Check out the Environmental Working Group’s Guide to Sunscreens to find out how well your sunscreen rates on not only UVB but UVA protection. Get more tips about staying safe in the sun and protecting yourself from skin cancer. (Photography: Thinkstock)