Summarize the following:
Think about how quickly you burn on a sunny day. Multiply that number in minutes by the sun protection factor (SPF) of the sunscreen you're considering. The result will tell you the maximum amount of time the sunscreen will keep you protected.  For example, if your skin turns red after 10 minutes in the sun, a sunscreen with SPF 15 should allow you to spend 150 minutes (2.5 hours) in the sun. No matter how quickly or slowly you tend to burn, the American Academy of Dermatology recommends using a sunscreen that is at least SPF 30. While higher SPF sunscreens do offer more protection, there is relatively little difference in the degree of protection offered by SPFs higher than 50. Sunscreen also cannot fully protect you from potentially harmful UVA radiation, no matter how high the SPF is. Keep in mind that wearing a high SPF sunscreen does not mean that you should avoid other protective measures, like staying in the shade, minimizing your time in the sun, and wearing protective clothing. The sun emits ultraviolet (UV) light in long-wave (UVA) and shortwave (UVB) rays. Both can cause skin cancer, but not all sunscreens contain UVA protection. Check the front of the packaging for terms like “Broad Spectrum.” This indicates protection from both kinds of UV rays. Mineral sunscreens may not contain the irritants that many chemical sunscreens contain. Zinc oxide and titanium dioxide are the most common active ingredients in mineral sunscreens. Both zinc oxide and titanium dioxide can make some people break out. If you are prone to breakouts, look for sunscreens that are labeled “noncomedogenic” (meaning they will not clog your pores). Read the packaging carefully. Look for oil-free formulas. If you have acne-prone skin, purchase sunscreens labeled “Non-Comedogenic.” These formulas won't clog your pores. Look for terms like “cream,” “lotion,” or even “ointment” on the front of the packaging. Moisturizing sunscreens are often formulated as these skincare products. Check for moisturizing ingredients like oil and lanolin.
Use the SPF that's right for you. Be cautious even when wearing high SPF sunscreens. Look for complete UV protection. Choose mineral sunscreen for sensitive skin. Buy sunscreen formulated for oily skin if you're prone to breakouts. Purchase moisturizing sunscreens if you have dry skin.