A double-blind trial of a zinc sulphate/citrate complex and tetracycline in the treatment of acne vulgaris.

Forty-eight patients participated in a 3-month double-blind study to compare the effect of orally administered zinc sulphate/citrate complex and tetracycline hydrochloride in acne vulgaris. Tetracycline significantly reduced the overall grade, and the number of non-inflamed lesions, papules and pustules by the third month. It also reduced significantly the non-inflamed lesions and papules at the end of the second month. In contrast, zinc therapy only had a significant effect on the pustules at the third month. The results indicate that tetracycline is far superior to the zinc complex in patients with moderately severe acne.