Think you know your SPF? Think again. Today, we’re tackling the grey areas of sun protection—from what SPF numbers really mean, to why the term “broad spectrum” is so important. We spoke with dermatologist and sun expert, Dr. Elizabeth Tanzi, and asked her our most burning questions (or rather, the questions to keep our skin from burning). Lucky for us, she was more than happy to explain everything we could possibly want to know about SPF.
Click through the slideshow above for five surprising SPF facts you NEED to know!
Surprise—a higher SPF number doesn’t always mean you’re getting more protection. “There is very little difference [between] an SPF 30, 50, or 100 when it comes to blocking UV rays,” Tanzi says. The SPF number is a measure of how long it would take for you to burn if you weren’t wearing any sunscreen, as opposed to the time it would take with sunscreen on. An SPF of 30 blocks about 97% of UVB rays, and anything above that increases by only one or two percent. Tanzi advises that how often you apply your sunscreen is much more important than how high the SPF rating is: “It is far better to use an SPF 30 [often], than an SPF 50 without reapplying,” she says.
SPF protects you against UVB rays, which cause sunburns, but not UVA rays, which is linked to deeper skin damage and the culprit for aging skin. UVA rays cause issues like wrinkling, brown spots, coarsening, hyperpigmentation, and more. Both types, however, can contribute to skin cancer, which is why she recommends always looking for products labeled as “broad spectrum” (more on that later).
You may not know this, but there are actually two different types of sunscreen: mineral and chemical. “Mineral sunscreens are ‘physical’ sunscreens and contain zinc or titanium,” Tanzi says. They deflect the sun’s rays, instead of absorbing them, like chemical sunscreens do. Both are FDA-approved, but many people may prefer mineral sunscreens because they’re made with more natural ingredients.
“Broad spectrum refers to the products ability to block both UVA and UVB rays,” Tanzi says. “In the past, most sunscreens just blocked UVB rays, but we now know that UVA is very damaging to the skin also.” Always choose a sunscreen labeled as broad spectrum to protect your skin from both!
One last surprising fact—SPF may not be enough to fully protect you. “Most people may not realize that sunscreen is NOT 100% perfect even if you use a lot,” Tanzi says. “That’s why you can get tan even when you use a lot of it!” Applying SPF is just one part of protecting your skin from the sun—she says it’s also important to cover your skin with clothes, seek shade, and wear hats and sunglasses with UV protection.
Click here for our editor-approved roundup of the BEST new sunscreens!