Why a Higher SPF May Not Be Enough
Dr. Edward Pullen

Why a Higher SPF May Not Be Enough

When buying sunscreen, most of us look at the SPF (sun protection factor) and figure the higher the number, the better.

Unfortunately, it's not that simple.

The sun is a natural full-spectrum source of light, and most of the damage to human skin comes from the ultraviolet range. Ultraviolet A (UVA) rays penetrate deeply and cause both desired tanning and undesired premature aging and skin cancer. Ultraviolet B (UVB) rays cause sunburn as well as skin cancer.

Today's SPF ratings reflect protection from UVB rays, but they don't indicate how much UVA protection is provided.

To make sure you get UVA coverage, look for sunscreens labeled "broad spectrum," which means the product protects against both UVA and UVB rays. However, there is no rating system for broad spectrum protection -- so even if a sunscreen is labeled "broad spectrum" and has a sky-high SPF, there's no way to gauge how much UVA protection you're actually getting.

Fortunately, the FDA recently announced new labeling requirements that will make it easier to understand sun protection ratings for both UVA and UVB rays, as well as provide more details about water resistance and how often a sunscreen needs to be applied to be effective. But these labeling requirements don't go into effect until next summer.

So what should you do this summer?

- Look for sunscreens that have an SPF of 30 or higher and are labeled "broad spectrum" and "water resistant."

- Don't skimp! For liquid sunscreens, use at least one ounce -- that's about one shot-glass full. If you use a sunscreen spray, make sure to apply a complete, even layer.

- Apply sunscreen frequently -- aim for every two hours.

- Wear protective clothing, which offers more protection than any sunscreen.

Personally, I find the most important guideline for sunscreen is to use it every time I even think I may be in the sun. Otherwise, I often find I end up getting more sun exposure than I want after a change in plans or weather. It's far better to have a layer of sunscreen on your skin when it clouds over than to not have applied it when the sun shines.

Dr. Edward Pullen is a board-certified family physician practicing in Puyallup, Wash. In addition to practicing full-service family medicine since 1983, he writes the medical blog DrPullen.com.

Twitter: @ihavenet

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