Glutathione
Glutathione is an endogenous tripeptide (glutamate-cysteine-glycine) that serves as the body's principal intracellular antioxidant and detoxification cofactor, and is used exogenously in oral, topical, and injectable forms for antioxidant support and skin-lightening purposes, with evidence quality varying considerably by route and indication.
This page is a research-orientation summary, not a dosing guide. For anything beyond general background, read the primary literature or talk to a qualified clinician — specifics like amount, frequency, or administration aren't something we publish here.
What it does & how it works
Glutathione's reactive cysteine thiol group allows its reduced form (GSH) to directly neutralize reactive oxygen and nitrogen species and to serve as the electron donor for glutathione peroxidase-mediated reduction of peroxides, becoming oxidized to glutathione disulfide (GSSG), which is then recycled back to GSH by glutathione reductase using NADPH. GSH also acts as a substrate for glutathione-S-transferases in phase II detoxification of xenobiotics and heavy metals, and helps regulate redox-sensitive signaling pathways such as Nrf2-driven antioxidant gene expression, which in turn influences melanin synthesis pathways relevant to its use as a skin-lightening agent.
Typical results seen in research
In a randomized controlled trial, six months of oral glutathione supplementation measurably raised glutathione stores in blood, plasma, lymphocytes, and buccal cells in healthy adults, confirming that oral dosing can increase body glutathione levels over time. In elderly patients with type 2 diabetes, a separate randomized trial found that long-term oral glutathione supplementation reduced markers of oxidative DNA and lipid damage and modestly improved HbA1c compared with placebo. For its popular use as a skin-lightening agent (oral, topical, or intravenous), a systematic review concluded that evidence of efficacy is limited and inconsistent across formulations and that safety data — particularly for high-dose intravenous use — remain insufficient, with case reports of adverse effects linked to unregulated injectable use.
How it’s commonly used
Glutathione is used via oral capsules or tablets (including liposomal or sublingual formulations intended to improve absorption), topical creams/serums, and intravenous or intramuscular injection, most often for general antioxidant support or, particularly with topical and IV routes, for skin-lightening purposes. It is also commonly taken alongside precursor nutrients such as N-acetylcysteine or alpha-lipoic acid, which are used to support the body's own glutathione synthesis rather than supplying glutathione directly.
- Front Pharmacol · 2014 Glutathione: new roles in redox signaling for an old antioxidant
- Curr Protein Pept Sci · 2019 Glutathione, an Antioxidant Tripeptide: Dual Roles in Carcinogenesis and Chemoprevention
- Eur J Nutr · 2015 Randomized controlled trial of oral glutathione supplementation on body stores of glutathione
- Antioxidants (Basel) · 2022 Randomized Clinical Trial of How Long-Term Glutathione Supplementation Offers Protection from Oxidative Damage and Improves HbA1c in Elderly Type 2 Diabetic Patients
- Indian J Dermatol Venereol Leprol · 2016 Glutathione as a skin whitening agent: Facts, myths, evidence and controversies
Curated from published literature for research orientation. Not an exhaustive review, and not a substitute for reading primary sources.