Health & Fitness

Self-tanning products: How do they work?

The deleterious effects of self-tanning products — streaky brown or Oompa-Loompa orange skin — have faded considerably over the past couple of years, due in large part to advances in formulations and delivery methods that make a DIY tan easier to acquire.

These advances, coupled with a stronger awareness of sun damage and the potential harmful effects of UV lights in tanning beds, have inspired more of us to slather on the bronze, rather than run the risk of skin cancer or premature aging.

U.S. sales of self-tanning products increased 13 percent in 2010 compared with 2009 ($22.9 million versus $25.8 million). Which may lead you to ask: How do these creams, lotions, foams and sprays work?

The active ingredient in the formulas that are misted onto the skin in a sunless tanning salon as well as the self-tanning products you'll find at drugstores and department stores is called dihydroxyacetone (or DHA), often derived from sugar cane or beets.

"The DHA binds with proteins in the stratum corneum (top layer of the skin) and undergoes a series of chemical reactions similar to what happens when you brown bread," says Randy Wickett, a professor of pharmaceutics and cosmetic science at the University of Cincinnati.

He adds that DHA doesn't react with the deeper, more viable part of the skin; it reacts with only the most superficial layer, which is constantly exfoliating itself — and that's why a sunless tan generally lasts from two to 10 days.

"The color created by the DHA reaction is more yellow and less red than natural skin color," Wickett says. "And unless you put something else in there, DHA will leave the skin orange."

Which is why many of the original self-tanners sold in the 1960s and '70s were notorious for turning the user's skin an ochreous hue, rather than a more natural bronze. During the past several years, the addition of another sugar compound called erythrulose has tempered the orange and produced a more natural-looking color.

DHA is approved by the FDA for cosmetic use, and Wickett adds that he hasn't seen any indications that the ingredient is unsafe.

Heather Roberts, an L.A.-based dermatologist, says that people should do two patch tests on an arm before applying a self-tanner to the entire body.

"The reaction is similar to poison oak," she says. "You may not see it in the first application. Apply it once and wait 48 to 72 hours to ensure there's no breakout or adverse reaction. Perform the test again a week later for a better safety margin."

And since some self-tanning formulas include ingredients such as beet juice, caramel and chocolate to amp up the color in the skin dying process, potential tanners with food allergies should be sure to check product labels.

Roberts also reminds self-tanners that a golden color is not an indication that skin is less sensitive to the sun.

"Self-tanners do not protect you from sun damage," she says. "People must use SPF after the sunless tanning product is applied."

Exfoliating is the most important step to keep the results of self-tanner looking even. Sloughing off the oldest skin cells and exposing the freshest layer of stratum corneum gives the tan a chance to last longer while clearing the skin of rough and flaky spots.

As formulations of self-tanners have evolved, so has the product packaging. In some cases, the word "tan" has been replaced with terms such as "skin finishing" and "glow products" in order to emphasize healthy, natural-looking skin.

Jergens has an extensive line of "glow lotions" that supposedly enhance the skin's natural color and add a healthy tone.

For anyone who is squeamish about applying any color-changing product to their entire body, there is also a growing market of wash-off self-tanning products that disappear with water.

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