It’s time to shed some light on SPF! The highly misunderstood SPF rating, which stands for Sun Protection Factor, is a way of measuring how well sunscreen protects the skin from UVB rays—the rays that lead to blistering sunburns and sometimes even skin cancer.
But alas, you’ll find SPF 15, 30, 50, 75 and many others on store shelves. So how do you choose? Well, to keep things simple, most dermatologists recommend going with a sunscreen rated between 15-30 SPF.
Here’s why. . .
If you’re exposed to the sun without any sunscreen, you could get the full effect of those pesky photons penetrating your skin. Apply 15 SPF and now you’re enjoying 93% protection from UVB. Go with SPF 30 and voila! 97% protection. Not bad.
From here, moving up the SPF ladder might make you feel good, but it’s really just a clever marketing ploy. You’re already 97% protected with SPF 30, so there’s very little room for improvement even if you slather on SPF 100.
Regardless of which SPF sunscreen you choose, if you only apply half the required amount, you do not get half the protection. Rather, you only receive a tiny fraction of the sunscreen’s protection. There’s nothing like wasting $15 on a tube of sunscreen and going home with a wicked sunburn (ouch!). And remember, the protective agent fades away within 1-2 hours, so it’s important to replenish throughout the duration of your exposure to the sun.
Finally, SPF does not measure protection from UVA rays, which are also damaging to our skin’s DNA.
Hopefully now you have a better grasp of what SPF means and how it does, and does not, keep you protected.