What SPF Do I NeedThere are SO many sunscreens out on the shelves everyone seems to be asking the same question” What SPF Do I Need? There is no question skin cancers are related to sun exposure, yet even with sunscreen sales approaching $1 billion a year, skin cancer rates continue to climb.

You know you need to protect yourself from the sun, but what’s right for you? It really comes down to understanding what is in sunscreen, your lifestyle and some simple math.

Sunscreens combine several ingredients to help prevent the sun’s ultraviolet radiation from reaching your skin. There are two types of ultraviolet radiation: UVA and UVB. UVB is the chief culprit behind sunburn, while UVA rays penetrate the skin more deeply and increase aging conditions from the sun.

The SPF Factor

SPF, or Sun Protection Factor, is a measurement of a sunscreen’s ability to prevent UVB from damaging the skin.


According to the American Council on Exercise, using some math can help you choose the right SPF for you.
Estimate how many minutes your skin can be exposed to the sun before the skin starts to burn.
Figure out the total number of minutes that you will be in the sun, then divide by the number of minutes it takes your skin to burn. The resulting number is the SPF you should look for in a sunscreen.

The Formula

If it takes your skin about 10 minutes to burn and you plan on being outdoors for 3 hours, then,

180 minutes / 10 minutes =
SPF of 18 or higher

In a recent article from the Skin Cancer Foundation, sunscreens vary in their ability to protect against UVA and UVB. Although UVA rays are associated with wrinkling, leathering and other light-induced effects of aging, they also exacerbate the carcinogeneic effects of UVB rays, and increasingly are being seen as a cause for skin cancer on their own. They recommend using a broad-spectrum sunscreen that offers protection against both UVA and UVB rays.

They also warn that no sunscreen can block all UV rays – and –

“No sunscreen, regardless of strength, should be expected to stay effective longer than two hours without reapplication. Reddening of the skin is a reaction to UVB rays alone and tells you little about what UVA damage you may be getting. Plenty of damage can be done without the red flag of sunburn being raised.”

To read their full article: http://www.skincancer.org/prevention/sun-protection/sunscreen/sunscreens-explained

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