Following is a really great article from this months Vogue, a clear and concise piece on the basics of buying and using SPF.  Don’t have the time to read?  Important highlights underlined.

The Numbers Game: When it comes to sunscreen, how much protection do we really need? Cristina Mueller on SPF 50, 80, 100…

What’s so complicated about sunscreen? In theory, nothing: You put it on, you go outdoors, you don’t end up looking like an old bag, end of story.  Right?  Right.  But then comes the following question: If we know sunscreen works (indeed, it is the number-one most effective antiager/skin-cancer preventer available, a miracle cream if ever there was one), how much do we really need?

Not so long ago, SPF 15 was the gold standard.  In recent years, dermatologists have settled on a sun-protection factor of 30 as a healthy baseline for daily use, which is why we find it in everything from moisturizers to foundation and lip balms.  But what are we to make of the 50s, the 80s and even the 100s?  And why stop at 100 – when is SPF 1,000 coming out?

Where SPF is concerned, numbers can be misleading.  While an SPF 30 blocks about 97 percent of the sun’s damaging rays, 50 blocks 90 percent – just 1 percent more. As the numbers go higher, the jump in protection becomes so negligible, infinitesimal is the word the Skin Cancer Foundation uses to describe it. The difference between SPF 50 and 100?  A meager 1 perfect, says Dr. Darrell Rigel, M.D., clinical professor of dermatology at New York University Langone Medical Center.  As a result, and in an effort to cut through the confusion, the FDA has proposed a cap moving forward, limiting all sunscreens over SPF 50 to simply be labeled 50+.

What’s the takeaway? “The ideal SPF for the average person is at least 30.” says Ronald Moy, M.D., professor of dermatology at the David Geffen School of Medicine at UCLA and past president of the American Academy of Dermatology.  He advises making the jump to 50 or higher “for people who are very fair or are prone to skin cancer.”

Another reason to consider the added security – even of it is the tiniest bit – of one of the stratospheric SPFs: It’s hard to say whether or not you are getting the level of protection indicated on the label in the first place.  If you smooth your sunscreen on with a light hand, as many people do, chances are you are not. “People do not apply sunscreen at the concentration the FDA tests at,” explains Rigel.  His recent study in the Journal of the American Academy of Dermatology found that when people were left to their own devices to apply their usual amount of an SPF 100 (between a quarter to half the recommended dose), they ended up with coverage in the vicinity of only 25 to 50.  The solution is of course to use the correct amount right from the start: a teaspoon to the face, and an additional shot glass-ful for the body, reapplied every two hours (no matter how high the SPF) when in direct sunlight or after a swim.

When it really comes down to it, what’s potentially skin-saving isn’t necessarily the number on the bottle but the indication that what’s inside offers broad-spectrum protection.  This means defense against both UVA and UVB rays.  Though the term broad spectrum has been thrown around rather generically, much like the unregulated natural and organic buzzwords, the FDA is now strictly monitoring these claims, requiring companies to pass stringent testing in order to advertise it on their labels.  And this, some dermatologists say, might be the biggest development yet: knowing once and for all that the sunscreen you’re relying on for its skin cancer-preventing, age spot-thwarting properties is doing the whole job it claims to do.  “Whether you’re using sunscreen or a daily moisturizer or makeup with sunscreen in it, make sure it says ‘broad spectrum,’” says Robert Friedman, M.D., clinical professor of dermatology at the New York University School of Medicine. “Otherwise, you’re wasting your time.”

All from Vogue, April 2013: written by Cristina Mueller, edited by Sarah Brown

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