UVB rays cause redness and sunburns, while UVA rays cause even more damage that penetrates deep in your skin fueling cancers and ugly age spots. Be sure to apply a sunscreen that offers you protection from both UVA and UVB rays - checking the label for that exact phrase. Also remember to apply broad-spectrum sunscreen even on cloudy days as clouds do not block UVA rays, which means that your skin is still being damaged even if you are not burning.
2. Consider physical sunscreens
There are two overriding sunscreens: chemical and physical. Chemical sunscreens absorb UV light and turn it into heat that comes off the skin, while physical sunscreens contain tiny bits of metal or minerals that reflect the light. Due to their lack of chemicals, physical sunscreens are marketed as natural and typically use zinc oxide and/or titanium dioxide to block out the sun. Chemical sunscreen, though effective, needs a little time to work - about 15 to 30 minutes, while physical sunscreen works immediately.
3. Reapply, reapply!
This is a guideline that most people ignore. You need to reapply sunblock at minimum every two hours in order to get natural protection. And always reapply if you have been swimming, sweating, or wiping your skin with towels. In addition, your lips need frequent sunscreen re-application as they are more delicate than normal skin and don't have the same photo-protective elements.
4. Sometimes, sunscreen isn’t enough
While sunscreens are good, if you are outside in peak sun in the middle of the day you are not going to be completely protected. For this reason, it is recommended to stay out of the sun in the middle of the day, when the sun's rays are strongest and always wear protective clothing, hats, and umbrellas.