Science
Mechanism of Action
While reduced glutathione (GSH) is the primary active antioxidant, GSSG is its oxidized counterpart, formed after GSH neutralizes free radicals. GSSG can be recycled back to GSH within cells, contributing to sustained antioxidant defense. In skin, it helps inhibit tyrosinase activity through direct antioxidant action, copper chelation, and interfering with tyrosinase transport, leading to reduced melanin production. It also encourages a shift towards lighter phaeomelanin synthesis and supports skin detoxification.
Research
Clinical Evidence
Medium confidence2%
Key findings
- 01 A 10-week, double-blind, placebo-controlled clinical trial involving healthy women aged 30 to 50 years demonstrated significant improvements with a 2% oxidized glutathione lotion applied twice daily. Participants experienced a marked reduction in skin melanin index, increased stratum corneum moisture content, suppressed wrinkle formation, and enhanced skin smoothness. The treatment was well-tolerated.
Transparency
Dusting Analysis
Clinical efficacy has been established at a 2% concentration. While lower percentages might offer some antioxidant benefits, significant claims regarding skin brightening, hydration, or anti-aging should be supported by a minimum of 2% in a formula.
The Formula
Formulation
Stability
Oxidized glutathione (GSSG) exhibits greater stability in aqueous solutions compared to its reduced form (GSH). A 2% GSSG lotion in a clinical trial was formulated at a pH of 6.46. While the powder is stable for extended periods at 2-8°C, aqueous solutions are not recommended for prolonged storage; they can be kept at 4°C for up to 7 days or -20°C for up to one month. High concentrations may lead to gel formation, and prolonged ultrasonic treatment should be avoided during formulation.
Conflicts
- strong oxidizing agents
Safety
Safety Profile
Topical application of a 2% oxidized glutathione lotion has shown good tolerability in clinical studies, with only one instance of mild, transient erythema reported. The Cosmetic Ingredient Review (CIR) has not yet reviewed this ingredient. EWG Skin Deep rates Oxidized Glutathione with low concern across various toxicity categories. It's important to differentiate this from intravenous glutathione, for which FDA warnings regarding potential contamination exist.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Oxidized Glutathione is a valuable ingredient, clinically demonstrated to brighten skin, enhance moisture, and reduce signs of aging, with good topical tolerability.
Related
Similar Ingredients
Finding similar ingredients…