The single most important thing you can do to prevent skin damage and reduce your risk for cancer is to avoid sun exposure. Take steps to protect your children or grandchildren from sun exposure, too, because most sun damage that leads to skin cancer occurs early in life. For enthusiasts of the great outdoors, sun protection is not an easy task. But careful selection of a sunscreen, protective clothing, and wise timing of activities can go a long way toward preventing further skin damage. One additional reason to use protective hats and other clothing is that sunscreen use has not been shown to protect against basal cell carcinoma as it does against other forms of skin cancer.
Sun block, Sunscreen, and More There's a difference between sun blocks and sunscreens. True to their name, sun blocks prevent the sun from reaching your skin. If you've ever been a lifeguard, you're probably familiar with the sun-blocking agent zinc oxide, the creamy white coating that has saved many a nose from too much sun. Zinc oxide and its chemical cousin, titanium dioxide, are sun blocks because they reflect ultraviolet radiation away from the skin surface. Both are available in skin tones and fashion colors, while titanium dioxide is also available in a clear formula. These ingredients are used in some commercial lotions such as those labeled as "non-chemical" or "for sensitive skin." Sun blocks are highly effective in protecting against UVA and UVB rays (see "Don't get burned by improper sunscreen use").
Sunscreens, on the other hand, absorb rather than reflect UV radiation. In recent years, the most widely used sunscreen ingredients have included benzophenones, which protect against UVA, and cinnamates and salicylates, which protect against UVB. You'll see these ingredients listed as oxybenzone, octyl salicylate, or octyl methoxycinnamate, to name a few. A major drawback is that many of these ingredients break down after several hours when exposed to sunlight, which means that the sunscreens need to be reapplied to be effective.
But two new sunscreens — Anthelios SX and Helioplex — provide longer-lasting protection against UVA and UVB rays. Research shows that Anthelios SX, which was approved by the FDA in 2006, retains 80 percent of its UVA protection and 90 percent of its UVB protection five hours after application. The product combines a new UVA absorber called ecamsule with an older UVA absorber (avobenzone) and an older UVB absorber (octocrylene). Helioplex is a stabilized formulation of avobenzone and oxybenzone, a longstanding UVB and UVA absorber. Helioplex and Anthelios SX appear to be comparable in sun protection and stability.
When choosing a sunscreen, most people look at the product's sun protection factor (SPF) rating. The American Academy of Dermatology (AAD) recommends using sunscreen with an SPF rating of at least 15. People with fair skin or at high risk for skin cancer may want to go higher. The higher a sunscreen's SPF rating, the longer it protects against sun exposure.
But that's just part of the equation. The SPF rating only measures how well a sunscreen blocks or absorbs UVB rays. Therefore, the academy and federal public health agencies advise using a sunscreen that protects against both UVA and UVB rays. Products labeled "broad spectrum" often contain several different sun protection ingredients in order to cover the broadest possible range of UV radiation. But to what extent they do so is difficult to determine because there is no good method of measuring how well a sunscreen protects against UVA. It's an issue the FDA is grappling with in developing new sunscreen labeling regulations.
