Everything You Need to Know About Sunscreen SPF
What is SPF?
It’s the first thing we all look for when picking out sunscreen, but what is it? How exactly does it work?
SPF, or Sun Protection Factor, is a number that indicates the amount of solar exposure it will take for your skin to start burning given the use of said sunscreen, versus the amount it would take if you didn’t wear any sunscreen.
To get even more specific:
SPF 15 blocks 93% of UVB radiation
SPF 30 blocks 97% of UVB radiation
SPF 50 blocks 98% of UVB radiation
Sunscreen SPF Testing
The numbers can get confusing, but you don’t need to worry about the trustworthiness of the label. All sunscreens must pass various FDA-approved tests before they hit the market. The FDA also regulates sunscreen marketing to ensure consumers are getting the information they need to stay safe. Here are some of the most important requirements:
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Broad spectrum
“Broad spectrum,” protection from both UVA and UVB rays, can be added to the SPF label if the sunscreen passes the FDA broad spectrum test. But only broad spectrum sunscreens with an SPF of 15 or higher can claim to defend against skin cancer and skin aging.
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Water and sweat resistance
First things first, no sunscreen can ever include the label “waterproof” or “sweatproof” since that would be overstating sunscreen’s effectiveness (water and sweat wear down all sunscreens eventually). To be called water or sweat resistant, a sunscreen’s SPF must remain effective for either 40 minutes or 80 minutes while swimming or sweating.
Beyond the numbers
Whether you’re wearing a 15, 50, or 100 SPF sunscreen, there are other things you’ll need to keep in mind to protect your skin! Don’t forget to consider:
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Amount of sunscreen
While amounts may vary depending on the person, you should generally aim for at least two tablespoons to cover your body and face, or until you reach an even shine if you’re using spray sunscreen. Don’t forget to protect your lips, too!
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Reapplication frequency
Ever been sunburnt after you swore you put on enough sunscreen? You probably didn’t reapply frequently enough. You should be reapplying at least every 80 minutes, and even more often after swimming, sweating, or drying off with a towel.
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Skin type
If you think you don’t need sunscreen because of your skin type, think again! While it’s true that some skin types burn much more easily than others, everyone is susceptible to the damaging effects of the sun.
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Expiration Date
It might be tempting to just slap on the sunscreen you’ve had laying around forever. But sunscreen actually does expire. Overtime, the active ingredients break down and don’t perform as well, so to make sure you stay protected, it’s best to throw out your sunscreen after a maximum of 3 years—no matter the SPF level.
