The Guru Guide to SPF
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According to the Skin Cancer Foundation, one in five Americans will develop skin cancer by the age of 70; in the U.S., more than two people die of skin cancer every hour. If fear isn’t enough to have you reaching for the sunblock, consider things from a vanity perspective: Those who apply sunscreen with an SPF of 15 or higher daily show 24 percent less skin aging than people who don’t wear SPF every day.
To review the ins and outs of proper sun protection, Bluemercury sat down with plastic surgeon Gregory Bays Brown, MD, founder of RéVive Skincare, and got his expert advice.
Why is daily sunscreen application so important?
Even if the planet wasn’t changing, which it is, as time goes on, we’re exposed more and more noxious stimuli, including increased UV radiation, increased gamma radiation, free radicals—all of that. UV radiation damages the skin, and you get mutations that stay with you for life. I always say, “The damage that occurs from the sunburn you get at 16 stays with you until you leave the planet.” It’s cumulative and much easier to prevent than to try to reverse once it occurs.
And wearing sun protection reduces your chance of developing skin cancer, correct?
Absolutely. The link between skin cancer and sun exposure has been known for a long time. The first sunscreens just protected against UVB rays, which primarily cause burns. UVA rays penetrate more deeply, and they actually mutate DNA, which obviously leads to bad things. I think the most important aspect of UVA exposure is not only that it decreases skin firmness and causes sagging and wrinkles and all of those things, but it’s also mutagenic and can cause malignancy. When you’re looking for a sunscreen formula, you need to seek out something labeled “broad spectrum.” That indicates that it protects against UVA and UVB rays. The SPF number actually only relates to UVB rays, so that alone isn’t a good way to evaluate a sunscreen.
What’s the difference between chemical and mineral sunscreens? Both are great. Chemical sunscreens (such as avobenzone and octisalate) work by absorbing UV rays and converting them to infrared rays, which are heat. If someone has melasma, rosacea or a similar condition, however, this heat can actually make their condition worse. Whereas physical sunblocks, like titanium dioxide or zinc oxide, actually reflect the rays off of the skin, so you don’t get the added infrared heat production.
And what’s the deal with nanoparticles?
They really only concern true physical sunblocks, which are very, very difficult to get right because if they’re not well-formulated, they tend to make you appear ghostly. And if they don’t, that means they’re probably made with nanoparticles, which are not good from either a health or an environmental standpoint. A nanoparticle, by definition, is less than a hundred billionth of a meter. Particles that small can be absorbed into the bloodstream and—theoretically—not do good things. And the same is true to the environment.
How much sunscreen do you need to apply to your face?
About a nickel-sized amount for your whole face.
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What about to your body?
We say a shot-glass size, which is a lot of cream. I think the reason the FDA monograph says apply liberally is because people use things sparingly, and they don’t necessarily apply enough. You want to be covered. If you miss a spot, that’s a spot that’s exposed. People often forget about areas like the scalp, ears, eyelids, lips and the tops of the feet, so you want to be sure to get those places as well. Applying in front of a full-length mirror will help ensure that you don’t miss anything.
What level of SPF do you need during the week, when you’re primarily indoors?
You always need sunscreen, but an SPF 15 probably is enough. And it needs to be broad spectrum, of course, for both UVA and UVB coverage. And it’s ok if it’s in your moisturizer. Our day creams often have an SPF 30, and I tell people that’s enough for living life or going to work on a regular day. But if you’re going to do an activity, like golf or tennis or be in a boat, then you should add more on top of that.
What about on the weekend, when you have a chance to be outside more? Well, most literature will say SPF 30. However, I think you need an SPF of 50 because 30 will take care of 95 percent of what you’re exposed to, but that added 5 percent is worth trying for.
How often do you need to reapply?
At least every two hours when you’re outside—more often if you’re swimming or sweating. A chemical sunscreen needs to be absorbed by your skin in order to be effective, and that process takes 15 minutes. So if you’re using a chemical sunscreen, you need to apply it at least 15 minutes before you step out of the house for the first time. And then reapply before you hit that two-hour mark. However, a mineral sunscreen lays on the surface of your skin, so you’re instantly protected the moment you put it on. But regardless of what type of sun protection you’re using, you need to reapply frequently, if you’re outdoors.
Any sunscreen myths you’d like to dispel?
That they’re bad. A couple of years ago, people were saying that sunscreens prevented you from getting enough vitamin D and that you were healthier with some sun exposure. I think that’s all bologna. In reality, sunscreen is very, very important. Its benefits far outweigh a little loss of vitamin D. I always say the most important anti-aging cream anyone can have is a sunscreen.
