Before 2012, manufacturers only had to put the SPF rating on the bottle. That told people how well the product is anticipated to protect against ultraviolet B rays, or UVB rays. Those are the ones that cause sunburns and the other maladies. An SPF 30 will filter out roughly 97 percent of damaging rays, while SPF 50 cuts out 98 percent of them.

Keep in mind that this isn’t a real numbers game, and there’s no such thing as an invincible shield against sun damage, no matter what number is on the bottle. Most SPF 30 sunscreens basically offer the maximum protection levels you can attain. After all, the difference between SPF 30 and SPF 50 is 1 percent. Even if you go up to SPF 100, you may wind up – that’s may – with protection in the 99 percent range. But that’s not a license to spend hours and hours in the sun because any prolonged exposure can defeat the chemical barrier you think you’ve erected. The sun is relentless and always “on” during the day, so any exposure counts against your daily total.

In fact, the Food and Drug Administration has called SPF labels touting 50 or higher protections to be “inherently misleading.” Countries in Europe, plus Japan and Canada, agree and prohibit anything being labeled higher than SPF 50.

Worse, while higher ratings may give some indication of better protection against UVB rays, they do little to tell you how much they guard against ultraviolet A rays, which can cause photo aging and lead to skin cancer. Your ethnicity, skin tone and age are also factors in what provides the best skin care. Toddlers have different needs than adults, while those whose skin is dry may have a different requirement than the acne-covered teenager.

What's Best for You?

The key is determining which sunscreens provide so-called “broad-spectrum” protection against both UVB and UVA rays. These have been certified by the United States Food and Drug Administration to provide protection against both types of sun damage.