Glutathione as an oral whitening agent: A randomized, double-blind, placebo-controlled study

TLDR: Oral glutathione administration results in a lightening of skin color in a small number of subjects, however, long-term safety has not been established and warrants more extensive clinical trials.

Abstract: Objective: To determine whether orally administered glutathione, 500 mg per day for 4 weeks, affects the skin melanin index, when compared with placebo. Methods: This randomized, double-blind, two-arm, placebo-controlled study was set in the King Chulalongkorn Memorial Hospital, Bangkok, Thailand, a teaching hospital affiliated with a medical school. Sixty otherwise healthy medical students were randomized to receive either glutathione capsules, 500 mg/day in two divided doses, or placebo for 4 weeks. The main outcome was mean reduction of melanin indices measured at six different sites. Several secondary outcomes, including UV spots, were recorded by VISIA™. Efficacies of glutathione and placebo were compared by ANCOVA with baseline values as co-variates. Results: Sixty participants enrolled and completed the study. At 4 weeks, the melanin indices decreased consistently at all six sites in subjects who received glutathione. The reductions were statistically significantly greater than those recei...