Glutathione
Glutathione (GSH, gamma-glutamyl-cysteinyl-glycine)
Also known as: GSH, Reduced glutathione
The body's master intracellular antioxidant tripeptide, used to support redox balance, detoxification, and skin, with mixed clinical evidence for supplementation.
Overview
Glutathione is a tripeptide of glutamate, cysteine, and glycine that is the principal antioxidant inside human cells and a key cofactor for detoxification enzymes. Its biochemistry is very well established, but oral bioavailability is poor and clinical evidence for supplemental glutathione (oral, liposomal, nebulized, or intravenous) is mixed. It is widely sold as a supplement; injectable glutathione is not an FDA-approved drug and compounded injectable forms have been flagged by regulators.
Mechanism of action
Neutralizes reactive oxygen species directly and via glutathione peroxidase, recycles other antioxidants, and conjugates toxins for elimination through glutathione S-transferases.
Key studies & citations
- Human2015
Randomized controlled trial of oral glutathione supplementation on body stores of glutathione
Six-month RCT in 54 adults: oral GSH (250 or 1,000 mg/day) raised blood and erythrocyte glutathione 17 to 35% and lowered oxidized-to-reduced GSH ratio; levels returned to baseline after washout.
European Journal of Nutrition - Human2018
Oral supplementation with liposomal glutathione elevates body stores of glutathione and markers of immune function
One-month pilot in 12 adults: liposomal GSH raised whole-blood GSH up to 40% and reduced oxidative-stress markers; small, uncontrolled, preliminary.
European Journal of Clinical Nutrition - Review2026
FDA reminds compounders not to use dietary supplement grade glutathione for injectables
Injectable glutathione is not an approved drug; FDA linked at least 30 adverse events (fever, chills, shock-like symptoms, hospitalizations) to endotoxin-contaminated compounded IV glutathione made from supplement-grade material.
U.S. FDA (Human Drug Compounding)
Frequently asked questions
Does oral glutathione raise glutathione levels?
Oral glutathione is poorly absorbed. Some studies report modest increases in body stores over time, but results are mixed and precursors like NAC are often studied instead.