Is self-tanner carcinogenic?

To date, no international health agency—whether the FDA, ANSM, or the EU’s SCCS—has classified dihydroxyacetone (DHA), the molecule used in most self-tanning products as a carcinogen. Available data show no genotoxic or mutagenic effect in vivo when DHA is used at authorized concentrations.

To understand the mechanism, we must distinguish two pigments: melanin, produced by dermal melanocytes under UV exposure, and melanoidins, formed by a chemical reaction between DHA and amino acids in the stratum corneum. This Maillard reaction, nonenzymatic, leads to brown pigment formation without melanin involvement. It is not physiological tanning but a localized artificial coloration at the skin surface. UV-induced tanning, which reflects the skin’s defense response to damage and increases skin cancer risk, must be distinguished from the brown coloration achieved by applying a self-tanner.

Getting a tan without sun exposure can alter sun-related behavior. Artificially darkened skin can give the illusion of increased protection, which may reduce vigilance. A study of 2,005 South Australians found that regular self-tanner users were more likely to develop sunburn than non-users, despite more frequent sunscreen application. This paradox raises important questions. Several hypotheses may explain it. On one hand, the amount of sunscreen applied may be below the recommended 2 mg/cm² needed to deliver the stated protection factor. On the other hand, reapplication, essential every two hours or after swimming, may be neglected.

In addition, a 2015 US survey of more than 27,000 adults found that 6.4% of respondents reported using self-tanner. Although self-tanner is presented as a safe alternative to UV tanning, the study found that these users engage in risky behaviors : they use tanning booths more often, experience more sunburns, and wear less protective clothing or seek shade to shield from UV rays, even though they apply sunscreen. These data raise the question of whether self-tanner alters sun exposure habits or coexists with risky practices without correcting them.

By coloring the skin, a self-tanning product can create a false sense of sun protection.

In summary, a self-tanner colors the skin without sun exposure and to date does not show carcinogenic effects. Its mechanism relies on the formation of melanoidins on the surface without activating melanogenesis. Note that it offers no UV protection. Artificial tanning does not protect against UV rays. To maintain skin health, applying a self-tanner does not replace rigorous, repeated sun protection.

• RODER D. M. & al. Use of fake tanning lotions in the South Australian population. Medical Journal of Australia (2001).

• DRAELOS Z. D. & al. Self-Tanning Lotions. American Journal of Clinical Dermatology (2002).

• MCKENZIE J. & al. Australians’ use of fake tanning lotions: another piece of the puzzle. Australian and New Zealand Journal of Public Health (2003).

• BRONAUGH R. L. & al. Fate of chemicals in skin after dermal application: does the in vitro skin reservoir affect the estimate of systemic absorption? Toxicology and Applied Pharmacology (2004).

• FOX J. L. & al. Review: ultraviolet radiation and skin cancer. International Journal of Dermatology (2010).

• IVERSON D. & al. Do Australian adolescent female fake tan (sunless tan) users practice better sun-protection behaviours than non-users? Health Education Journal (2011).

• BONIOL M. & al. Reviews on sun exposure and artificial light and melanoma. Progress in Biophysics and Molecular Biology (2011).

• MARTINI M.-C. Autobronzants et bronzants artificiels. Annales de Dermatologie et de Vénéréologie (2017).

• LIEBMAN T. N. & al. Dihydroxyacetone and sunless tanning: knowledge, myths, and current understanding. Journal of the American Academy of Dermatology (2017).

• LINOS E. & al. Characteristics and skin cancer risk behaviors of adult sunless tanners in the United States. JAMA Dermatology (2018).