Key words: self-tanning products, dihydroxyacetone, DHA


In the contemporary world, sun-tanned skin has been considered a sign of good health and fashionable lifestyle. As a result, a substantial number of people sunbathes and exposes their skin to UV radiation generated by solar lamps to make their skin look darker. UV radiation activates tyrosinase and increases melanocyte proliferation, which stimulates melanogenesis and the production of pigmented biopolymers, the so-called melanins. Melanins concentrate in keratinocytes in the area of nucleus and absorb UV radiation, which protects the skin against damage resulting from exposure to natural and artificial light, and neutralize active oxygen. However, severe UV exposure, in particular, shortwave radiation, may reduce the skin’s protection barrier and induce skin irritations. Recurrent exposure accelerates photo-ageing manifested by increased stratum corneum thickness, chronic inflammations, dysfunctions of sebaceous glands, telangiectasias, hyperpigmentation, and wrinkle formation. Moreover, this is the basic risk factor of the development of skin neoplasms, wherein the carcinogenicity applies to both, shortwave and long-wave radiation (UVB and UVA).
Suntanned skin still remains fashionable; however, people are more and more aware of the negative aspects of longterm exposure to sun. Consequently, the demand is growing for self-tanning preparations providing similar effects to natural suntan without the above-mentioned side effects, and in particular, without the risk of accelerated photoageing and the development of neoplasms.
As an alternative to sun- and solar tanning, special cosmetic preparations may be used, which produce brown skin color similar to natural tan in reactions between active browning agents and epidermal proteins from stratum corneum. In particular, alpha-hydroxy ketones react with amino acids from the peptide structures of keratinocytes (Maillard reaction) to produce water-insoluble pigments – melanoidins, and to temporarily produce a brown color to the superficial layers of stratum corneum. Skin tanning preparations contain, in particular, dihydroxyacetone (1,3-dihydroxy-2-propanone) and L-erythrulose ((S)-1,3,4-trihydroxy-2-butanone), as well as quinone derivatives: lawsone (2-hydroxy-1,4-naphthoquinone) and juglone (5-hydroxy-1,4-naphthoquinone).
These compounds quickly react with proteins to produce melanoidins of suitable color.
Dihydroxyacetone is primarily used as an ingredient in sunless tanning products.