Maybe you're stuck under cold, gray skies, dreaming of lying on a beach somewhere feeling the sun's warming rays. But in lieu of that, you figure why not get an indoor tan from a salon?

Well, here's why not.

According to a study in the journal Science Advances, tanning bed users develop twice as many genetic mutations (alternations in their DNA) as people who don't use tanning beds, and those mutations are in places that are not normally exposed to the sun but do get zapped in a tanning bed.

Add to that the fact that tanning-bed users are at a 300% greater risk of developing the most serious form of skin cancer, melanoma, often at a younger age than usual.

No wonder the World Health Organization classifies tanning beds as a "group 1 human carcinogen," similar to asbestos or cigarette smoke.

The Cleveland Clinic says that a good alternative is a sunless tanning lotion or cream that contains Food and Drug Administration-approved DHA (dihydroxyacetone; it's not DHA-docosahexaenoic acid, which is found in omega-3s).

DHA reacts with dead cells on the skin's surface and darkens them temporarily. But if applied as a spray or aerosol, beware. Don't inhale or get into your eyes.

For information on how to have great skin (and avoid skin cancers), check out my books, "YOU: Being Beautiful: The Owner's Manual to Inner and Outer Beauty" and "The RealAge Makeover: Take Years Off Your Looks and Add Them to Your Life."