|UVA rays--damage, no sunburn.|
Adam Friedman, MD, director of dermatological research at the Montefiore Medical Center in NY, tries to spell out the latest FDA thinking on sunscreen.
First, sunscreens claiming to be waterproof and sweat proof weren't. Now these are "water resistant." If it says 80 mins, reapply before that.
Sunscreens with SPF-2 to SPF-14, can prevent sunburn, but not cancer or premature aging.
The FDA, by the way, has yet to decide whether SPF-50 is really good additional protection.
Whatever the value, you need to glom it on--a full ounce--usually people use a quarter of this.
Sunscreens now protect against two types of rays--UVB and UVA. UVA does not cause sunburn (warning) and thus is more dangerous.
Look for products with a few blocking agents--ecamsule, cinoxate, octyle salicytate, and oxybenzone.
Apply at least a shot glass full of 30-50, reapply every two hours--what the heck, wear a hat and clothes, also.
Me, I stay in.