DHA is primarily used as an ingredient in sunless tanning products. It is often derived from plant sources such as sugar beets and sugar cane, and by the fermentation of glycerin. This is why it is important for those with diabetes to provide House Beauty with a note to confirm treatment may take place.
DHA was first recognized as a skin coloring agent by German scientists in the 1920s. Through its use in the X-ray process, it was noted as causing the skin surface to turn brown when spilled.
This skin browning effect is non-toxic, as DHA reacts chemically with the amino acids in the skin, which are part of the protein containing keratin layer on the skin surface. Various amino acids react differently to DHA, producing different tones of colouration from yellow to brown. The resulting pigments are called melanoidins. These are similar in colouration to melanin, the natural substance in the deeper skin layers which brown or "tan", from exposure to UV rays.
Copper tone introduced the first consumer sunless tanning lotion into the marketplace in the 1960s. This product was called “Quick Tan” or “QT”. It was sold as an overnight tanning agent, and other companies followed with similar products. Consumers soon tired of this product due to unattractive results such as orange palms, streaking and poor colouration. Because of the QT experience, many people today still associate sunless tanning with fake-looking orange tans.
Sunless tanning products contain DHA in concentrations ranging from 1% to 15%. Most drugstore products range from 3% to 5%, with professional products ranging from 6% to 20%. The percentages correspond with the product colouration levels from light to dark. Lighter products are more beginner-friendly, but may require multiple coats to produce the desired colour depth. Darker products produce a dark tan in one coat, but are also more prone to streaking, unevenness, or off-colour tones. The artificial tan takes 2 to 4 hours to begin appearing on the skin surface, and will continue to darken for 8 hours, depending on formulation type.
Once the tan has fully developed it needs to be washed off with plain water in a shower (never a bath). The water will run orange until the developer has completely washed off and underneath you will be left with a natural looking tan. The developer is not coloured, though the majority of tans have a guide colour bronzer added (that instant colour you get when you've first had your tan applied) in order for the technician to see where they are applying for a full and even coverage.
Once the darkening effect has occurred, the tan will not sweat off or wash away with soap or water. It will fade gradually over 3 to 10 days, in conjunction with the skin's normal exfoliation process. Exfoliation, prolonged water submersion, or heavy sweating can lighten the tan, as these all contribute to rapid dead skin cell exfoliation (the dead skin cells are the tinted portion of the sunless tan.)