Survey of chemical substances in consumer products, 72 – Assessment of DHA in self-tanning creams applied in spray booths

Assessment of DHA in self-tanning creams applied in spray booths

4 Substances contained in products

The number of self-tanning products on the market is growing, and more manufacturers of self-tanning booths are making their own products. The products assessed in this project are water-based, with a water content of 75-85 per cent. A review of the information on packaging, websites, patents (4) etc. revealed the following information about 15 self-tanning products for spray application on the market. DHA, bronzers and moisturisers are the most common ingredients in this type of commercially available self-tanning product. The remaining ingredients mentioned in 4-11 below are common in many self-tanning products.

Dihydroxyacetone (DHA). Ordinary self-tanning agents typically contain 3-14 per cent DHA. Self-tanners sold over the counter contain lower concentrations of DHA (typically 3-5 per cent) than self-tanning products used in professional spraying booths (typically 8-14 per cent). The highest concentrations are in the agents used in modern spraying booths where the consumption of lotion is reduced and the concentration of DHA is increased in order to achieve a better tanning effect (1).
Bronzers. Many self-tanning products contain an ordinary dyestuff (bronzer) which colours the skin immediately after application. This means that it is easy to see where the self-tanning product has been applied and therefore avoid missed patches without DHA. Many customers also seem to like seeing an immediate effect. It is important to stress that the bronzer does not influence the final effect of the self-tanning product. The bronzer washes off in the shower. The most common bronzers, which are also described in the patents, are caramel, Carmine (CI 75470) and various nut oils from, for example, chestnuts and walnuts.
Moisturisers are also used by most manufacturers. The most common are glycerine and various plant extracts, e.g. aloe.
Erythrulose is also contained in some self-tanning products as an active self-tanning substance, either on its own or in combination with DHA.
Perfumes, e.g. cinnamyl alcohol, citral, citronellol, dipentene, geraniol, hexyl cinnamaldehyde, hydroxycittronellal, lilial, linalool.
UV filters (4,5).
1. Without nitrogen: e.g. dicaprylyl ether (CETIOL OE).
2. UV B filters: Ethylhexyl Methoxycinnamate, Methylbenzyliden Camphor.
3. UV A filters: Benzophenon-3, Butyl Methoxydibenzoylmethane (AVOBENZONE).
Preservatives. Parabens (methyl-, ethyl- and propylparaben are contained in many products) and phenoxyethanol (4).
Thickening agents. Cellulose ethers and xanthane gel are often used (4).
Emulgators. Silicones, sesquioleates, sorbitan esters, alkoxylated sorbitan and fatty-acid esters, alkoxylated mono-, di- and triglycerides, alkoxylated polymers, alkoxylated fatty alcohols, fatty acids, esters and ethers of natural oil derivatives are often used.
Vitamins: A, E and C.

Chapter 5 includes a toxicological profile of DHA as well as brief profiles of erythrulose, ethoxydiglycol, phenoxyethanol, glycerine, polysorbates/sorbitan esters, parabens and PCA/Sodium PCA. These substances have been selected on the basis of their occurrence in many self-tanning products.