Dihydroxyacetone, DHA
Dihydroxyacetone, commonly referred to as DHA, is
the active ingredient in most
sunless tanning and
self tanning products.
DHA is a non-toxic colorless sugar, it's the sunless
tanner chemical responsible for giving us the tan
color. When DHA is applied to the skin it reacts with
the amino acids of dead skin cells in the outermost
layer of the epidermis (the stratum corneum) forming
melanoidin-like brown-colored compounds. The
concentration of DHA in
sunless tanning lotions
and
self tanning towelettes
determines the shade of tan as well as the rate
with which the tan develops.
Once applied DHA takes 2 to 3 hours to fully react
with the skin. After this has occurred DHA cannot be
washed off, instead the color fades as the upper layers
of the epidermis are naturally sloughed off over a 5
to 7 day period. To maintain a
sunless tan,
regularly reapply
self-tanning products
every 3 to 4 days.
One final word on DHA, there are people who may
experience an allergic reaction to dihydroxyacetone.