Within the past year a number of similar cosmetic preparations have appeared on the market and have been extensively advertised for their "tanning" effect on the skin. In our practices we have received numerous inquiries regarding their effectiveness and safety. There seems to be a general impression on the part of the laity that the artificial tan which these agents produce will protect against sunlight.
This investigation was undertaken to determine the possible sun-screening properties and effect upon melanogenesis of dihydroxyacetone, the active ingredient in these preparations.
Experiment I
Ten healthy white male volunteers were used. Three test areas, each measuring 1×1 inch (2.5×2.5 cm.), were marked out on the external aspect of one arm of each subject. Dihydroxyacetone lotion* was applied to one of these test sites. Twenty-four hours later this site was given a 4+ erythema dose of ultraviolet light produced by Westinghouse FS4OT-12 fluorescent ultraviolet lamp. The