Mark I. Gimbel, M.D., is a surgical oncologist with Banner MD Anderson Cancer Center in Gilbert
Question: I know I need to wear sunscreen when outdoors, but what should I look for in a product?
Answer: The options are so plentiful that choosing a sunscreen can be confusing. What you do want is a sunscreen with an SPF, or sun protection factor — that's the percentage of ultraviolet-B (UVB) rays that will be prevented from penetrating the top layer of the skin, thereby causing a sunburn of at least 30. Make sure it's also labeled as a “broad spectrum” sunscreen. That indicates it also protects the skin from UVA rays, the other kind of solar radiation. Because they penetrate deeper into the skin, UVA rays tend to cause aging effects, like wrinkles, and boost the rate of melanoma. Although they are messy and difficult to rub into the skin, sunblock products with zinc oxide or titanium dioxide are safe alternatives that work very well, diffracting 100 percent of ultraviolet rays.
Just remember, even when using a broad-spectrum sunblock or a sunscreen with an SPF of at least 30, you need to use it correctly by applying to all exposed skin about a half hour before venturing outside. Then, make sure you reapply it every two hours. If you're sweating a lot or swimming, you may need to apply it more frequently. Limiting your sun exposure is also important, and, of course, never use a tanning bed. There's no clinical need for them, and the increased risk of melanoma for women has increased tenfold in the past several years due to their use.