Sunscreen is essential but buying sunscreen can be very confusing. From water resistant sunscreens to SPF to broad spectrum protection, it is hard to know what you need to keep your skin safe this summer. Sunscreens protect you from the sun's ultraviolet (UV) radiation from reaching your skin. There are two types of ultraviolet radiation, UVA and UVB. They both damage your skin and increase your risk of skin cancer. The difference between UVA and UVB Ultraviolet (UV) radiation is part of the electromagnetic (light) spectrum that reaches the earth from the sun. Ultraviolet A (UVA) is the longer wave UV ray that causes lasting skin damage, skin aging, and can cause skin cancer. Ultraviolet B (UVB) is the shorter wave UV ray that causes sunburns, skin damage, and can cause skin cancer. The definition of SPF SPF stands for Sun Protection Factor. The SPF number on sunscreen is a measure of a sunscreen's ability to prevent UVB from damaging the skin. The number of the SPF is how long it will take the sun to redden the skin. For example, SPF 15 sunscreen theoretically prevents reddening 15 times longer than no sunscreen at all– about five hours. What is broad spectrum? Sunscreens that have broad-spectrum protect the skin from both UVA and UVB rays. Beginning in December 2012, the U.S. Food and Drug Administration (FDA) will implement new rules for "broad-spectrum" products. New sunscreen rules Here are some of the new rules The US Food and Drug Administration (FDA) has issued for labels on sunscreen. • Sunscreens may be labeled “broad- spectrum” if they provide protection against both UVA and UVB radiation according to FDA-sanctioned test methods. • Only broad-spectrum sunscreens with an SPF of 15 or higher may state that they protect against skin cancer if used as directed with other sun protection measures. • Broad-spectrum sunscreens with SPFs of 2-14 must display a warning that the product has not been shown to help prevent skin cancer or early skin aging. • The terms “sunblock,” “sweatproof” and “waterproof” are no longer allowed on sunscreen labels. • Sunscreens may claim to be “water-resistant,” but must specify whether they protect the skin for 40 or 80 minutes of swimming or sweating, based on standard testing. Sunscreens that are not water-resistant must instruct consumers to use a water-resistant sunscreen if swimming or sweating. • A company cannot claim that its sunscreen products provide sun protection for more than two hours without submitting test results to prove this.