Oral zinc sulphate therapy for acne vulgaris.

A double-blind controlled clinical trial was performed to evaluate the effect of oral zinc sulphate, 0.6 g daily, on acne vulgaris. Twenty patients received zinc sulphate tablets and 19 were given placebo tablets. Thirteen of the zinc group and 12 of the placebo group received their medication throughout a 12-week period, while the remaining patients were treated for 4 or 8 weeks. In all patients the numbers or papular and pustular acne lesions on the face and the back were significantly reduced, while larger infiltrates remained practically unaltered during the trial, which was performed from March through May 1975. No statistically significant difference in the improvement of the groups was demonstrable. Pretreatment serum zinc values, which were normal in all patients, rose significantly in the zinc group as well as in the control group, but the increase in the former was significantly higher. The negative therapeutical results might be attributable to the limited number of patients or related to the zinc dosage. Furthermore, the results might have been influenced by the unexplained rise in serum zinc values in the control group. A possible weak beneficial effect of zinc might also have been camouflaged by the seasonal variation in the severity of acne which was noted in this study.