Q: I’d like to keep the tanned look I got during summer vacation. Are self-tanning lotions and sprays a good idea? Are they safe to use?

 
A: When you sunbathe, the sun’s ultraviolet (UV) rays cause the skin to increase its production of a protective pigment called melanin, which manifests itself as a tan. Despite its association with good health and good looks, a tan is actually a sign of skin-cell damage, which can increase the risk for skin cancer and accelerate skin aging. The American Academy of Dermatology recommends using self-tanning lotions and sprays as an alternative to tanning in UV light from the sun or an indoor tanning bed.

You can buy self-tanning products over the counter and apply them yourself or go to a salon that offers spray-on or airbrush tans. The active ingredient in all of these products is dihydroxyacetone (DHA), a color additive approved by the FDA for tanning purposes. DHA binds to proteins in the top layer of skin, causing it to darken or stain. Thicker, protein-rich areas of your skin will stain more. That’s why exfoliation of the elbows, knees, and ankles is recommended beforehand for even results. Because the coloring process takes place only in the surface layers of the skin, your “tan” lasts only as long as those layers stay on your body — about five to seven days. After that, you’ll need a reapplication.

Although self-tanning is generally considered safe, few safety studies have been published. Allergic reactions are rare, but the long-term effects remain largely unknown. For now, the FDA has approved DHA for external use only, excluding the lips, eyes, ears, nose, and mucous membranes. A study found that DHA added to skin cells damaged proteins in the cells’ DNA, suggesting more research is needed before DHA can be declared safe for long-term use.

One very real concern is that many people who use self-tanners don’t practice proper sun protection afterward. Unlike a natural tan, self-tanning doesn’t confer any significant UV protection. Thus, anyone sporting a faux glow still needs to use sunscreen or sunblock when out in the sun.

If you opt for self-tanning at a salon, spa, or gym, be aware that the self-tanning industry is largely unregulated and few states exercise any oversight. During a spray-on tanning session, be sure your eyes, lips, ears, nose, and other mucous membranes are covered and that you hold your breath to avoid inhaling the product while it’s being applied.

— Celeste Robb-Nicholson, M.D.
Editor in Chief, Harvard Women’s Health Watch

This question and answer first appeared in the October 2006 Harvard Women's Health Watch, available at www.health.harvard.edu/women.