The Science

Glutathione as an oral whitening agent: a randomized, double-blind, placebo-controlled study 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 receiving placebo at two sites, namely the right side of the face and the sun-exposed left forearm (p-values = 0.021 and 0.036, respectively). This was similarly reflected in the changes in the number of UV spots, as measured by VISIA. Both glutathione and placebo were very well tolerated. Conclusion: 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. Read More

The efficacy of skin care products containing glutathione in delivering skin lightening in Indonesian women Abstract Glutathione is a potent antioxidant, which is widely used in skin care products for skin lightening especially in the Asian market. Presently, there was only one study of topical 2% oxidized glutathione (GSSG) in Philipino women, further study is needed to evaluate the efficacy and safety of cosmetic products containing glutathione. A double blind randomized clinical trial study was conducted in Yogyakarta, Indonesia, in 74 healthy Indonesian women, with average age 33.3 ± 5.9 years when subjects participated in the study. Each subject received supervised applications of Facial Wash twice a day, Day Cream with sunscreen and Night Cream. The subjects were divided into 3 groups based on the active ingredients of the tested products, which included glutathione reduced (GSH) 0.1%, GSH 0.5%, and without GSH. The effects of the tested products in lightening skin color and pigmentation were measured colorimetry with Chromameter Minolta for L*. Compared to a baseline, there were significant increases of L* (lightness) or ΔL* detected as early as week 2 in which group of GSH 0.1% were significantly higher compared to group of GSH 0.5% and group without GSH. Hyperpigmented lesions also improved, where GSH 0.5% group showed its superiority compared to others groups in week 8. The undesired effect were few minutes mild tingling sensation after night cream, and worsening of acne in all tested products. Conclusion skin care products containing GSH 0.1% and 0.5% were effective in facial skin lightening. Read More

The Effect of Cysteine Peptide Ingestion on Skin Brightness, a Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Human Clinical Trial Abstract Glutathione (GSH) is present in almost all human cells and has a beneficial effect on human skin brightness. Cysteinylglycine (Cys-Gly) and γ-glutamylcysteine (γ-Glu-Cys) are GSH synthesis components. In this study, we defined glutathione (GSH), cysteinylglycine (Cys-Gly), and γ-glutamylcysteine (γ-Glu-Cys) as cysteine peptide and performed a randomized, double-blind, placebo-controlled study to investigate the effects of orally administered cysteine peptide on human skin brightness using a CM-26d portable spectrophotometer in healthy males and females aged between 20 and 65 years old. Eligible participants were randomly allocated into three groups (cysteine peptide 45 mg: n = 16, 90 mg: n = 15, and placebo: n = 16). Each subject ingested six tablets every day for 12 weeks, and skin brightness was measured at 0, 4, 8, and 12 weeks. As a result, the 45 mg group exhibited arm brightening in a time-dependent manner, and a significant difference was observed compared to the placebo at week 12 (p = 0.028). Moreover, no serious adverse events and changes related to 270 mg study food were observed in the safety trial. Here, we suggest that cysteine peptide is a promising and safe compound for human skin brightness. Keywords: cysteine peptide; glutathione; cysteinylglycine; γ-glutamylcysteine; skin brightness; safety Read More