Expand Sunscreens work by using active ingredients that absorb, scatter, or reflect the UV radiation before it reaches the skin. By filtering out harmful UV rays, broad-spectrum sunscreens help to reduce the risk of skin cancer and premature skin aging, as well as help prevent sunburn. Source: "Sunscreens: How to Read a Label, Expert Tips Etc." Sunscreens: How to Read a Label, Expert Tips Etc. | Cosmetics Info. Accessed April 29, 2019. https://cosmeticsinfo.org/products/sunscreens-how-read-label-expert-tips-etc.