I tried sunbed tanning last year. Afterwards, I found a lot of little "growths," like more moles, on my skin. This year I am tempted to do it again, but I know it is not very good for one's skin. Can you give me advice regarding sunbed tanning -- is it really that dangerous?

-- Susan

Tanning beds are as damaging as the real thing -- and in some respects, maybe even more so. There are two major types of ultraviolet radiation -- UV-A and UV-B rays. UV-B rays are a shorter wavelength and tend to cause sunburn (you can think of B = burning). They also damage the DNA in the skin surface cells and cause skin cancer. UV-A rays are a longer wavelength and penetrate more deeply, into the dermis, the layer under the skin surface. There, these UV-A rays damage collagen and elastin, contributing to loss of elasticity of the skin -- these rays are responsible for the dry, leathery, wrinkly skin of the chronically sun-exposed (think of A = aging). UV-A rays may also contribute to melanoma, another type of skin cancer.

Tanning beds produce UV-A rays. While it is less likely (although by no means not impossible!) to burn in a tanning bed, those UV-A rays are still damaging the deeper layers. With continued exposure and passage of time, the signs of photoaging -- wrinkles, blotchy skin, dryness -- will appear.

More UV-A than UV-B rays reach the surface of the earth. Most sunscreens provide protection from UV-B rays, but most sunscreens do not protect against all the types of UV-A rays. Only those products containing Parsol 1789 (avobenzone) or zinc oxide protect against both UV-B and all UV-A rays. The smartest approach: wear a broad-spectrum sunscreen when outdoors and avoid tanning beds altogether. Maybe in a few years the pale skin that was so highly prized in the 1700s and 1800s will once again be in vogue.