The sunless tanner dihydroxyacetone (DHA) is currently the most popular way to gaining a tan without sun exposure. To date, it is the only ingredient approved by the US Food & Drug Administration (FDA) for sunless tanning. DHA has been used in cosmetics preparations to color the skin for over 30 years.
DHA is derived from glycerin (vegetable origin) and is made up of mostly water, sugar by products, aloe and vitamin E. DHA is not absorbed into the body and poses no possibility of toxicity. There are no oils in the solution so it does not clog pores.
The skin is made up of two main layers: the epidermis on the outside and the dermis on the inside. If you are talking about sun-tanning or self-tanning, the epidermis is where the action occurs. Epidermis is made up of layers. The deepest layer of the epidermis, called stratum basale (basal layer) is affected during sun tanning. The Stratum corneum is the outermost layer of the epidermis that is the layer that is affected by most sunless-tanning products.
The most effective product today are tanning lotions that contain DHA as the active ingredient. DHA interacts with the dead cells located in the stratum corneum of the epidermis. As the sugar interacts with dead skin cells, a color change occurs. This change usually lasts about 7 to 10 days from initial application.
Everyday, millions of dead skin cells are sloughed off or worn away from the surface of your skin. In fact, every 35 to 45 days, you have an entirely new epidermis. This is why tans from sunless or self tanning lotions will gradually fade as the dead skin cells are worn away, so is your tan. For this reason most of these products suggest that you reapply the sunless or self-tanner every week or two to maintain your tan.
