We all know the importance of using sunscreen each and every day. Especially living under the hot Texas sun in these hot summers. According the the American Cancer Society, applying sunscreen every day can reduce the formation of actinic keratoses (also called solar keratoses), a potential precursor to skin cancer.  But with so many sunscreens on the market and varying levels of SPF in each, how do you know what to use?

In an article posted on WebMD, American Academy of Dermatology (AAD) spokesman James M. Spencer, MD admits that SPF is not a consumer-friendly measure.  Logic would say that SPF 30 provides double the protection that SPF 15 does, but that’s not how it works.  According to Spencer, an SPF 15 product blocks about 94% of UVB rays, an SPF 30 product blocks 97% of UVB rays, and an SPF 45 product blocks about 98% of rays. “After that, it just gets silly,” he says. Sunscreens with higher SPF ratings block slightly more UVB rays, but none offers 100% protection.

Spencer says SPF 15 sunscreens are fine if used correctly, but he recommends SPF 30 products to his patients because few people apply sunscreens as heavily or as often as they should.  So, how often should you apply it?  An article by the Center for Disease Control has a good checklist:

When To Apply Sunscreen

  • Apply sunscreen approximately 30 minutes before being in the sun (for best results) so that it can be absorbed by the skin and less likely to wash off when you perspire.
  • Remember to reapply sunscreen after swimming or strenuous exercise.
  • Apply sunscreen often throughout the day if you work outdoors, and wear hats and protective clothing.

How To Apply Sunscreen

  • Shake well before use to mix particles that might be clumped up in the container. Consider using the new spray-on or stick types of sunscreen.
  • Be sure to apply enough sunscreen. As a rule of thumb, use an ounce (a handful) to cover your entire body.
  • Use on all parts of your skin exposed to the sun, including the ears, back, shoulders, and the back of the knees and legs.
  • Apply thickly and thoroughly.
  • Be careful when applying sunscreen around the eyes.