Fake Tan Photoprotects, but Not a Lot Having a tan may be so attractive to some people that they are beyond the reach of health educators. An available alternative is the fake tan induced by dihydroxyacetone (DHA). In recent years, improved application techniques have produced less streaky, more acceptable results. Researchers in Denmark investigated whether the pseudo tan produced by DHA photoprotects skin from burning. They compared the minimal erythema dose values of treated and untreated skin in 20 healthy volunteers. One of two concentrations of DHA cream (5% or 20%) was applied to the upper back and forearm of participants once or three times in the amount of 2 mg/cm2. Phototesting with a solar simulator source was performed 22 to 26 hours after the last application, and the SPF of various application variables was computed. On the back, DHA provided a SPF of 1.3 to 2.2, depending on concentration and number of applications. The SPF values for forearm skin were approxi­mately twice those seen on the back (4.3 after three applications of 20% cream). COMMENT: New application methods, such as spray-on devices, have improved the cosmetic appearance of DHA-darkened skin. Toxicologists tell us that DHA staining of the stratum corneum is relatively safe. It certainly produces a tan color acceptable to many users, but the SPF data presented in this study support a message that users need to hear: Despite the tanned appearance it produces, DHA confers only modest photoprotection. James Ferguson, MD Faurscbou A et al. Sun protection effect of I dibydroxyacetone. Arch Dermato1 2004 Jul; 140:886-7.