Divers, You’re Not Using Enough Sunscreen

Used to be that a sunscreen with a sun protection factor (SPF) of 15 was all you could get. Then the number rose into the 70s, and now Neutrogena has a SPF 100+ sunblock. Well, according to dermatologists, it’s only a marketing game.

Sunscreens with sky-high SPFs, or sun protection factor, offer only slightly better protection against sunburn than an SPF 30. While an SPF 100 blocks 99 percent of UVB rays, SPF 30 deflects 96.7 percent.

But that’s only if you apply enough, which most people don’t. You see, to get the SPF advertised, you must apply at least an ounce, the equivalent to a full shot glass, every time. And because sunscreens rub off or don’t stay put, dermatologists advise reapplying every two hours, or after swimming or sweating. Forget about “waterproof” sunscreen because on divers it all gets rubbed, washed, or sweated off anyway, so it needs to be reapplied often.

Done right, sunscreen can reduce skin cancers. Australian researchers had 800 people apply an SPF 16 sunscreen to their heads, necks and arms every morning, while 800 others applied sunscreen in their usual routine, which often meant not every day. The results: While people in both groups had developed the scaly skin patches that are precursors to skin cancer, those who used sunscreen daily developed 40 percent fewer.

Dermatologists recommend sunscreens with an SPF of at least 15 and UVA-fighting ingredients like avobenzone, Mexoryl SX, titanium dioxide and zinc oxide. A good sunscreen will contain at least one, preferably more, of these ingredients and, contrary to old reports, none of them are considered harmful to coral reefs or marine life when you’re in the water