IRA FLATOW: This is Science Friday. I’m Ira Flatow. Sunscreen use is on the rise. That’s the good news. The bad news, so are cases of skin cancer. What’s that all about? Well, it could be the type of sunscreen you’re using. A poor quality sunscreen might keep you from getting a sunburn, but it won’t shield skin from harmful ultraviolet rays that cause melanoma.

And recently, scientists with the Environmental Working Group tested almost 1,500 sunscreens, moisturizers, and lip balm that advertise sun protection. And they found that 73% of those products don’t provide the protection consumers think they’re getting. And one of those scientists is my next guest, David Andrews, senior scientist at the Environmental Working Group. Welcome to Science Friday.

DAVID ANDREWS: Pleasure to speak with you today, Ira.

IRA FLATOW: How can 73% of those products fail?

DAVID ANDREWS: Right, and so 73% of those products, huge percent. These are products that don’t meet our standards in terms of product efficacy, how good a job that they’re doing protecting us from both sunburn as well as those UVAs you were discussing, or contain concerning ingredients. So we did flag out products that we thought contained ingredients that may be a health concern.

IRA FLATOW: So what exactly makes a poor quality sunscreen?

DAVID ANDREWS: Well, most sunscreens, there’s a direct response to know whether or not it works. You apply the sunscreen, you spend some time in the sun, and if you didn’t have enough sunscreen or high enough SPF, you’ll know a few hours later, or the next morning. Your skin turns red. You’ve got a direct feedback whether or not you’re getting enough SPF protection or sun protection factor.

But whether or not that product is providing adequate UVA protection– and that’s really critical for reducing long term skin damage. It may lead to wrinkles, or play an important role in melanoma development. You don’t really get that feedback for potentially, decades. And so that’s why it’s critical for sunscreens to provide both the sunburn protection as well as comprehensive UVA protection really, as much as possible.

IRA FLATOW: Let’s talk about UVA that you’re mentioning, and UVB. There are two kinds of ultraviolet, correct? Give us the reasons that you need both of them.

DAVID ANDREWS: Right, these are two kinds of ultraviolet light, ultraviolet radiation that are emitted from the sun. The UVB radiation that I’m speaking about, this is higher energy light, and can react more directly with the skin. It can cause direct DNA damage. And actually, UVB light is predominately responsible for sunburns.

The UVA is a longer wavelength. This is ultraviolet light that’s actually closer to the visible spectrum. This is where you’re getting into the blue light. It also plays an important role in causing health impacts. And those are the longer term health impacts, especially melanoma development, and playing an important role in that, as well as long term skin cancer or long term skin damage, like wrinkles and skin aging.

IRA FLATOW: Do some products available here, do they contain the product that blocks UVA? Or do you have to– I remember being in London, shopping in Boots, their drugstore over there. And I could get suntan screen that had both protection in it. But when I came back to the States, it didn’t say that on the labels over here.

DAVID ANDREWS: In the last five years, we’ve actually seen a shift in a high percentage of products include at least some filtration for UVA. And that was due to a change made by the Food and Drug Administration in 2011. But we don’t think products are providing adequate amount of UVA protection, especially in relationship to the SPF on the label.

And so we think it’s imperative that those values be very balanced. For an example, a T-shirt will give you perfect balance across the entire spectrum. It’ll do just as well of blocking the UVA light as it does the UVB radiation.

IRA FLATOW: Is there is there an ingredient we should be looking for on the label?

DAVID ANDREWS: In the US?

IRA FLATOW: Yes.

DAVID ANDREWS: The two ingredients that stand out that provide the best UVA protection are zinc oxide. And that’s an ingredient that’s found in the majority of our top products. The other ingredient would be avobenzone. And it’s found in a concentration up to 3%. And we recommend seeking out products that would have 3% of that ingredient, and an SPF between 30 and 50, typically.

IRA FLATOW: So you should look into that. I mentioned the European sunscreens. Why are they not available, if they work better, in America?

DAVID ANDREWS: That’s a great question. And really, the FDA has kind of backed themselves into a corner here in many ways. How people use sunscreen has changed significantly in the past 30 years. Originally, people were using these products occasionally, beach holidays, to reduce sunburns. Now people are using sunscreens much more commonly daily often, covering large portions of their body. And so FDA has changed the amount of safety information they’re looking for before allowing new ingredients on the market.

At the same time, they can’t go back and request additional safety data for the ingredients that are already in products. So there’s a sliding scale of how much safety information the agency is looking for. But these new ingredients being used in Europe, Canada, and other places in the world, look to offer much better UVA protection. So we’re really in a tough spot, especially with the backdrop of melanoma rates, which have been rising at close to 2% a year for decades.

IRA FLATOW: And is it because we’re using them incorrectly, the ones that are available to us? I mean, are we putting them on every– they say on the label every 20 minutes after you go in the water. If you used it more like the label recommends, would you get better protection?

DAVID ANDREWS: You’ll definitely get better protection if you use it more often, you apply liberally, you reapply every two hours. One thing that we’re very concerned about is something called the compensation hypothesis. And what this hypothesis is that when people apply sunscreen, they change their behavior, and actually spend more time in the sun.

If you do that, you’re largely negating the benefits of the sunscreen. And so it’s imperative that you’re using sunscreen not to prolong your time in the sun, but as part of a sun protection strategy that includes hats, shirts, and seeking shade. You can’t just rely on sunscreen use alone to reduce the UV radiation, and reduce the long term skin damage and potentially cancer.

IRA FLATOW: So you have a false sense, then, of safety when you put it on.

DAVID ANDREWS: Oftentimes, that’s what we’re very concerned about, that people get a false sense of security, and then that false sense of security increases actually, when you use these higher SPF products. There’s products out there with SPF 100. It almost makes you feel like you’re invincible to the sun’s rays when you’re wearing this product, and may lead to what is ultimately damaging sun behavior.

IRA FLATOW: So does the SPF number above 50 mean anything? I mean, is it–

DAVID ANDREWS: This is a question that the Food and Drug Administration raised, that concerns that SPF values above 50 had little meaning for consumers. And actually, I think as an example of this issue, Procter and Gamble, just over five years ago, submitted an SPF 100 product that they bought off the shelves to four different testing labs around the country. And the results they got back varied from an SPF 74 all the way down to an SPF 37. And so none of them reproduced the SPF 100 on the label.

But an important point here is that the difference in UV radiation that went through that product, the difference between an SPF 37 and an SPF 100 is just over 1 and 1/2 percent. So it’s an extremely small difference in UV radiation hitting the skin. But it leads to this enormous difference in SPF number on the product. And so ultimately, there’s not very much difference between an SPF 35 and an SPF 100.

IRA FLATOW: So you’re saying just wear a T-shirt, you’ll get good protection.

DAVID ANDREWS: I think that’s a great idea. Wear a T-shirt. And in certain circumstances, you’ll definitely want to wear sunscreen. We think it’s an important part of reducing UV rays of sun safety. But be cognizant of not using a sunscreen to prolong the time you spend outside.

IRA FLATOW: There you go. Thank you very much for taking time to be with us today.

DAVID ANDREWS: My pleasure.

IRA FLATOW: David Andrews, senior scientist at the Environmental Working Group.

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