INDUCTION OF SKIN TANNING BY SUBCUTANEOUS ADMINISTRATION OF A POTENT SYNTHETIC MELANOTROPIN

Objective. - To determine the efficacy of short-term administration of a synthetic analogue of a-melanotropin, [Nle4D-Phe7 (NDP)-alpha-melanocyte-stimulating hormone (MSH), in darkening (tanning) human skin. Design. - Randomized, placebo-controlled, double-blind clinical trial. Setting. - Clinical research unit of a university medical center. Subjects. - Twenty-eight healthy white men with a history of either poor tanning (skin type I or II) or good tanning (skin type III or IV) recruited from advertisements and paid to participate in the study. Methods. - Each subject received 10 subcutaneous injections of either a purified NDP preparation or saline over 12 days. They were followed up for 7 weeks after therapy was completed. All subjects used a high-potency sunscreen during the the trial. Main Outcome Measure. - Skin darkening was quantified by serial chromaticity measurements prior to, during, and after therapy. Results. - A significant parabolic curve of skin darkening activity was noted in subjects with skin type I or II (P < .001) and with skin type III or IV (P << .001) who were given NDP. No darkening occurred in the subjects who were given a placebo. Peak changes were seen 1 to 3 weeks after therapy was completed. Conclusion.-Human skin darkens as a response to a synthetic melanotropin given by subcutaneous injection. Skin tanning appears possible without potentially harmful exposure to ultraviolet radiation.