With so much water all around us in Maryland, we’re all exposed to a lot of sun. The sun’s ultraviolet rays are the issue, penetrating the skin and damaging its cells, leading to skin aging and wrinkling, and various skin cancers. At the Laser Center, addressing skin cancer is one of our myriad services.
Sure we all know we’re supposed to go out covered head to toe like a mummy, but who wants to do that? So when our friends ask us out on their boat everybody simply slathers on the sunscreen. But what do you really know about sunscreen and how it protects, or doesn’t protect, you?
Sun protection factor (SPF) and UV radiation
You’ve seen the SPF on every sunscreen bottle or tube. This was a new addition to modern sunscreens and it stands for “sun protection factor.” SPF is not really a measure of protection, it is a measure of how long it will take for ultraviolet B (UVB) rays to redden your skin compared to having no sunscreen on. For instance, SPF 15 means that it will take 15 times longer with sunscreen on than without. Why does it use the UVB rays as the benchmark? Those are the rays that cause sunburn because they penetrate only the epidermis, the surface layer of the skin.
They don’t usually have this on the label, but the percentage of the rays a sunscreen blocks are also measured. An SPF 15 sunscreen screens 93 percent of the sun’s UVB rays; SPF 30 protects against 97 percent; and SPF 50 protects against 98 percent. The U.S. Department of Health and Human Services recommends only SPF 15 and higher for providing adequate protection. You can see that adding SPF over 15 doesn’t really change your protection much, although you can find SPFs of 100. This is mostly just a way to charge you more money!
Sunscreens have always focused on the UVB rays that burn the epidermis. But scientists now say UVA rays, which penetrate far more deeply, into the dermis layer of the skin, also cause skin damage and skin cancer. So, you need a sunscreen that protects against both UVA and UVB. To do this, look for a sunscreen with at least SPF 15, plus some combination of the following UVA-screening ingredients: avobenzone, ecamsule, oxybenzone, titanium dioxide, and zinc oxide. When you see a label that says broad spectrum or multi spectrum or UVA/UVB these indicate that some UVA protection is provided. However, there isn’t a measure of how much protection these terms denote.
How do sunscreens work?
The ingredients in sunscreens form a thin, protective film on the surface of the skin and absorb the UVA radiation before it penetrates the skin. The “sunscreens” are actually physically screening the sun, meaning that their insoluble particles reflect the UV rays back off the skin. The FDA has approved 17 active ingredients for use in sunscreens. The baby oil you used to put on in the backyard, uh, not one of them! In those days you were basically opting for the fry pan treatment.
Unfortunately, no matter how much you know about UVA rays and sunscreen, your skin will still suffer sun damage. That’s where our skin experts can help, checking for skin cancer and helping to address issues with sun damage. Call us at 410-544-4600 to schedule your appointment, and in the meantime wear that sunscreen!