9 Sunscreen Booby Traps to Avoid

When you do the math, you'll quickly see that if sunscreen is applied correctly, one 8-ounce bottle shared by a few family members or friends won't last past lunchtime, if that. The American Cancer Society (ACS) stresses the importance of applying sunscreen 15 to 20 minutes before going outside to let your skin absorb it. The ACS also recommends using sunscreen even on cloudy days. Also, use lip balm containing sunscreen.
 
Relying on only SPF numbers: Do you purchase sunscreen based only on SPF number listed on the bottle? Next time you're shopping, you may want to take a closer look at the label. SPF only measures UVB (ultraviolet-B) radiation protection, not UVA (ultraviolet-A) protection. Both types of UV light lead to skin damage and cancer so it's vital that sunscreens protect from UVA as well as UVB. Make sure the product specifies protection from both or says "broad-spectrum" on the label.

5 other sunscreen booby traps to know about:

• Despite advertising claims, no sunscreen is "waterproof" or "sweatproof," according to the FDA. "Water resistant" sunscreens must be reapplied after 40 minutes of sweaty activity or swimming.
• As crazy as it sounds, certain sunscreen ingredients break down in sunlight!  Some ingredients also break down over time, the FDA says, and that deterioration may be speeded by sun exposure. So throw away last year's bottles and keep your sunscreen in a shaded spot when outdoors. The Environmental Working Group, a public health advocacy organization, found that 54 percent of sunscreens contain ingredients that become unstable when exposed to light and might not offer the advertised protection. The group lists what it deems the "best" sunscreens here.
• Don't look for "sunblock." The FDA states that no product completely blocks UV rays. "Sunscreen" is a more accurate term.
• Watch out for human error and don't be frugal with sun protection. "Most sunscreen users still get burned because they do not apply enough sunscreen to begin with," Dr. Taylor says. Slather sunscreen on thickly, covering all exposed skin. Pay attention to the areas that usually get missed: ears, around the eyes, neck (all the way around!), hands, feet and toes.
• Use sunscreen or wear long-sleeved clothing when driving, since side-window glass can let in UVA rays as can some windows in buildings. And remember that water, sand, concrete and snow all increase the reflection of sunlight, so put on more sunscreen and shorten your exposure time.