Coppertone rolled out a SPF 70 last year, so Neutrogena came out with SPF 85.
This year, Banana Boat has an SPF 85, so Neutrogena came out with an SPF 100.
A New York Times article entitled
Confused About SPF? Take a Number points out that:
In 2007, the Food and Drug Administration proposed capping SPF at 50+, but it still isn’t set in stone. So in the cap’s absence, a marketing battle is raging..
and that:
The difference in UVB protection between an SPF 100 and SPF 50 is marginal. Far from offering double the blockage, SPF 100 blocks 99 percent of UVB rays, while SPF 50 blocks 98 percent. (SPF 30, that old-timer, holds its own, deflecting 96.7 percent). Doctors say proper application is the most important thing about sunscreen, and that most of us do it wrong. Docs say 1 oz (or enough to fill a shot glass) is what you need to cover your entire body in one application. In order to get the above effectiveness from the SPF 30, you have to apply enough.
UVA radiation causes burns, UVB rays cause skin damage and aging, and both can lead to skin cancer. So,
dermatologists now advise using sunscreens with an SPF of at least 15 and UVA-fighting ingredients like an avobenzone that doesn’t degrade in light or Mexoryl SX.
