Skin Cancer and UVA Rays

This is sort of a tangent but I’ve run into it while I’ve been researching cruelty-free sunscreens. Basically, I realized that most sunscreens don’t protect people from skin cancer — that only sunscreens with avobenzone, mexoryl, octocrylene, titanium dioxide, or zinc oxide in them will.

Why will these ingredients protect everyone from skin cancer? I read a ton of articles and blogs on this, and I finally determined the reasoning. Basically, there are two types of wavelengths in sunlight — UVA rays and UVB rays. People used to think that UVA rays were harmless and UVB rays caused skin cancer. This seemed logical because UVB rays were shown to cause tanning. So people slathered on sunscreens that protected them against UVB rays but did nothing to protect against UVA rays and spent more time out of doors exposing themselves to skin cancer than they would have if they hadn’t worn any sunscreen at all, and skin cancer rates started to skyrocket. Rates of sunscreen usage and skin cancer have increased dramatically since the 1970s – in the U.S. alone, new cases of melanomas have increased 150%, and deaths from melanomas have increased by 44%. A recent Australian study confirmed that the reason for this is that UVB-blocking sunscreens are not very effective at preventing melanomas. So scientists are attempting to determine what causes deadly melanomas, if it isn’t UVB rays, and many of them suspect that it’s the other ultraviolet component of sunlight — UVA rays.

So, I think it’s important to block those skin-cancer-causing-UVA rays. But will buying a “full spectrum” sunscreen block UVA rays? No. The Skin Cancer foundation recommends only five types of skin-cancer-blocking ingredients — avobenzone, mexoryl, octocrylene, titanium dioxide, and zinc oxide. If you do not buy a sunscreen with one of these ingredients, it will not protect you from skin cancer. Just be sure to turn over any sunscreen bottle you find in a store and read the active ingredients list to make sure it has avobenzone, mexoryl, octocrylene, titanium dioxide, or zinc oxide in it. Avobenzone is the best one — mexoryl is not available in the U.S. right now (but is rumored to begin to be available in the fall), octocrylene has weird hormone issues, and titanium dioxide and zinc oxide tend to cause streaks (yuck). Alba Botanica makes some great cruelty-free sunscreens with avobenzone in them that I really like — a facial sunscreen, a facial moisturizer with sunscreen, a water resistant sunscreen, and a kids’ sunscreen. I haven’t tried the water resistant sunscreen or the kids’ sunscreen, but the facial sunscreen and the moisturizer are excellent.

I figure that within the next five years the FDA or some government authority will require all sunscreens to have UVA-blocking ingredients if they wish to call themselves sunscreens, but in the meantime, it’s probably a good idea to think about buying one with avobenzone in it.

Update 04/21/07: I’ve read some rumors that avobenzone may “generate free radicals” or something like that. I’m not really sure what those are, and the only sites I’ve found that talk about this do not cite any scientific sources, and the Environmental Working Group, which I think is a reputable site, lists avobenzone of having a score of 0.0 on the toxic scale. So I’m leaving my recommendation of avobenzone up (for now). As soon as I find any articles saying that avobenzone is toxic on PubMed I shall stop recommending it. In the meantime, avobenzone does block UVA rays, which have caused numerous skin cancer deaths over the past decades, so I’m sticking with it. If you click on the link above, and type in “avobenzone,” you’ll see 41 scientific articles that have tested how well avobenzone protects against UVA rays.