Evaluating oral glutathione plus ascorbic acid, alpha-lipoic acid, and zinc aspartate as a skin-lightening agent: An indonesian multicenter, randomized, controlled trial

CLINICALTRIALS.GOV IDENTIFIER: NCT04105504. BACKGROUND: For Asians, especially women with darker skin tones (Fitzpatrick Skin Types IV and V), clear, bright skin is considered highly desirable, and various topical, oral, or injection-based cosmetic skin-lightening agents with different mechanisms of action are widely available across Asia. OBJECTIVE: We sought to investigate the effcacy and safety of an oral glutathione supplement comprising L-glutathione (fermentation), ascorbic acid, alpha-lipoic acid, and zinc (as zinc aspartate) as a skin-lightening agent. METHODS: This randomized, double-blind, controlled clinical trial was carried out at three teaching hospital-based dermatovenereology clinics in Indonesia. Participants were randomized to receive either the glutathione supplement or placebo capsules and were evaluated every four weeks over a 12-week study period. Total reduction in spot ultraviolet, spot polarization, and skin tone were measured and recorded using a Janus Facial Analysis System® (PIE Co., Ltd, Suwon-si, Gyeonggido, Korea). RESULTS: Eighty-three participants, aged between 33 and 50 years, completed the study. Reductions in spot ultraviolet in certain subgroups, spot polarization, and skin tone were greater in the glutathione supplement group than in the placebo group, but the difference was not statistically significant. Both the glutathione supplement and placebo groups experienced only mild side effects in the first four weeks. CONCLUSION: The oral glutathione supplement was slightly beneficial for skin lightening in particular subgroups, but the results were not statistically significant. Mild and temporary side effects were reported. Further research is required to more fully evaluate the effcacy of this glutathione supplement as a skin-lightening agent.