the sun as your worst frenemy: She’s warm and friendly to your face, but you know you can’t trust her—she’s going to do damage eventually. Sneaky UVA rays age skin by increasing free radicals, which disrupt DNA and slow collagen synthesis. UVB rays target the top layer of skin, which equals sunburn. Both cause skin cancer. You know how to fight back: sunscreen. Use a broad-spectrum formula (which protects against UVA and UVB rays) with an SPF of 30. Dr. Frances Jang, a dermatologist at Skinworks in Vancouver, recommends applying a topical antioxidant like vitamin C. At concentrations above 8 percent, it can enhance SPF because it’s anti-inflammatory and neutralizes free radicals. There’s also evidence that vitamins C and E may protect against damaging infrared rays, so expect to see more sunscreens containing these antioxidants.