How Do Self Tanners Work?

The principle tanning agent used in all self-tanning formulas is dihydroxyacetone (DHA).
This ingredient does not produce a "real tan" by increasing the skin's melanin levels,
rather it creates a tanned appearance by developing a brown color on the surface of the skin.
The action of DHA is limited to the upper layer of the skin and involves a reaction between DHA and skin proteins and oxygen that produces brown compounds. 
 This process is similar to what occurs when you slice open an apple and the surface of the apple browns when it's exposed to the oxygen in the air. 
The development of color takes anywhere from 2 to 4 hours and the intensity of color is dependent upon the DHA concentration in the product as well as each tanner's individual skin characteristics.
The color developed by the DHA usually lasts 5 to 7 days and begins to fade as the top layer of the skin naturally exfoliates. 

What is DHA (Dihydroxyacetone)?

According to the American Academy of Dermatology, the most effective sunless tanning products contain dihydroxyacetone (DHA) as the active ingredient. DHA is a colorless chemical (it is derived from glycerin) that interacts with the amino acids in dead skin cells to produce a brown color change. Since these dead skin cells are constantly being shed, the color change produced by DHA usually lasts about five to seven days.

DHA is not absorbed through the skin into the body and it has no known toxicity. DHA was first discovered by the Germans in the late 1920's when DHA spilled on the skin produced a brown color. DHA has been listed with the Food and Drug Administration (FDA) since 1973, and has been used in cosmetic preparations for almost 30 years.

Are there any restrictions about the use of DHA?

Yes, the use of DHA in cosmetics, including sunless "tanning" products, is restricted to EXTERNAL application only. According to the Code of Federal Regulations, "externally applied" cosmetics are those "applied only to external parts of the body and not to the lips or any body surface covered by mucous membrane. In addition, no color additive may be used in cosmetics intended for use in the area of the eye unless the color additive is permitted specifically for such use.

DHA solutions take about 16-hours to fully develop.
Clients will receive the best results if they can avoid bathing until the day after their sunless session.
 If they must bathe, they should wait a minimum of 6-hours after the application.
If showering prior to the 16-hour post application recommendation, a simple rinse with water only, is best. Soap destroys DHA.
Delayed bathing allows the DHA bronzer sufficient time to complete its reaction with the amino acids (proteins) within the skin.

What type of bronzers are used in Norvell® Sunless Tanning Solution?

Three different types of bronzers are used in Norvell® Sunless Solutions. First, there is the instantly visible Cosmetic bronzer. Cosmetic bronzer gives the "just off the beach" look, but will wash away.
 (For best results, cosmetic bronzers should remain on the skin at least 8 hours).   Bronzer type two is DHA. The DHA bronzer initially has no visible effect, but begins to react with the skin in 2-4 hours and eventually replaces the cosmetic bronzer as it washes away with bathing.
Finally, Eyrthulose is used as a slow-reacting bronzer, very similar to DHA.
Eyrthulose enhances the clients color and extends the life of the spray tan.