Kyowa Hakko (Tokyo) has announced the results of a new study on the ability of its proprietary glutathione antioxidant ingredient, Setria glutathione, to brighten skin. In a previous study, the ingredient, which has been shown to reduce melanogenesis in vitro, was found to help brighten dark spots at a dosage of 500 mg/day. The new study, which was published in the Journal of Clinical, Cosmetic and Investigational Dermatology,1 demonstrated Setria glutathione’s skin-brightening potential, even when administered at a lower dosage of 250 mg/day.
In the randomized, double-blind, placebo-controlled study, 57 healthy female subjects between the ages of 20 and 50 were given either a daily oral dosage of 250 mg of Setria glutathione (the reduced form of glutathione), 250 mg of AquaGluta glutathione (the oxidized form of glutathione), or a placebo. The researchers explain why they decided to study both forms of glutathione. They said that while glutathione exists in the body in both the reduced and oxidized forms and can be readily converted into each other, it is unclear “whether the two forms are physiologically similar, especially when melanogenesis is concerned.”
The participants were studied over the course of 12 weeks and were evaluated by the researchers at weeks 4, 8, and 12. At each visit, the study authors measured melanin index, per Mexameter MX 18 (a tool used to measure skin color). In addition, the researchers took photographs to evaluate UV spots, pores, and evenness in skin tone (using the Visia-CR imaging system); and measured transepidermal water loss (TEWL, via the Tewameter TM300), water contents (with Corneometer CM825), skin elasticity (with Cutometer MPA580), and presence of wrinkles (with Visioscan). Blood samples were collected for safety monitoring, and no adverse effects were recorded for the duration of the study.
The results of the study indicated that, while numbers in the melanin index were not significantly different for the study and placebo groups, the groups supplemented with either form of glutathione showed slightly lower levels of melanin. As the study authors note, melanogenesis results from exposure to UV radiation, causing the skin to darken. Decreased levels of melanin suggest brighter skin. In addition, researchers observed a significant difference in the Visioscan wrinkle measurements between the glutathione groups compared to the placebo—a trend that was reflected across participants of all ages. Finally, while the results did not indicate statistically different elasticity measurements, the groups given glutathione tended to have higher skin elasticity, the researchers said.
A Kyowa Hakko press release noted that, according to a recent report from Global Industry Analysts, the global market for skin lighteners is expected to reach $23 billion by 2020. Though the primary consumers of skin-lightening products have traditionally been women, personal grooming supplements are becoming increasingly popular among men as well, the press release notes. The company says this study further supports the efficacy of oral-delivery skin-lightening supplements.
Rachel Nazarian, MD, Fellow of the Academy of Dermatology, said in a press release: “This study on Setria glutathione suggests that when taken orally, Setria may decrease melanin production, lightening dark skin in individuals with Fitzpatrick skin types IV and V. When taken in doses of 250 mg per day, oral glutathione such as Setria is safe and well tolerated, with no evidence of any major adverse events. Given oral glutathione’s regulatory properties on melanogenesis and pigment production in the skin, this safe, reduced dosing may also help decrease the melanin index in individuals with darker skin tones.”
Kyowa Hakko funded this study.