# Glutathione

> Evidence tier A — Controlled human trials · Longevity & Immune · reviewed 2026-11-08
> Source page: https://peptidemeta.com/p/glutathione/

Also known as: GSH, Reduced glutathione, γ-L-Glutamyl-L-cysteinylglycine

## Quick answers

**What is Glutathione?**

The body's main antioxidant tripeptide, γ-glutamyl-cysteinyl-glycine (the glutamate is linked through its side-chain γ-carboxyl, not a normal peptide bond), critical for detoxification, immune function, and cellular redox balance.

**How strong is the evidence for Glutathione?**

Tier A (controlled human trials) on the peptidemeta evidence scale. Randomized controlled trials exist, e.g. a 6-month RCT of oral glutathione that raised the body’s glutathione stores (Richie 2015). Not an FDA-approved drug.

**Is Glutathione FDA-approved?**

No. Glutathione is not approved by the FDA for any use.

**Is Glutathione banned in sport?**

No. Glutathione is not on the World Anti-Doping Agency Prohibited List.

**How does Glutathione work?**

Glutathione (gamma-glutamylcysteinylglycine) is the principal intracellular thiol antioxidant that directly neutralizes ROS and reactive nitrogen species via its sulfhydryl group. It serves as a cofactor for glutathione peroxidase and glutathione S-transferase enzymes, driving Phase II hepatic detoxification.

**What is known about the safety of Glutathione?**

Endogenous molecule with a well-established safety profile. IV glutathione widely used in integrative medicine.

## Key facts

- **Evidence tier:** A (Controlled human trials)
- **FDA:** not approved
- **WADA:** not on the Prohibited List
- **Peptide:** yes
- **Sequence:** [γ-Glu]CG (3 residues)
- **Formula:** C10H17N3O6S
- **Molecular weight:** 307.3 g/mol
- **Routes studied:** Intravenous, Oral, Subcutaneous

## Overview

The body's main antioxidant tripeptide, γ-glutamyl-cysteinyl-glycine (the glutamate is linked through its side-chain γ-carboxyl, not a normal peptide bond), critical for detoxification, immune function, and cellular redox balance. Supplemented via IV, oral liposomal, or nebulized routes.

## Mechanism

Glutathione (gamma-glutamylcysteinylglycine) is the principal intracellular thiol antioxidant that directly neutralizes ROS and reactive nitrogen species via its sulfhydryl group. It serves as a cofactor for glutathione peroxidase and glutathione S-transferase enzymes, driving Phase II hepatic detoxification. The GSH/GSSG redox couple maintains cellular redox homeostasis critical for immune cell function.

## Effects reported in research

_Reported outcomes, not promises; see the evidence tier._

- Neutralization of reactive oxygen species
- Phase II liver detoxification support
- Immune cell function optimization
- Skin brightening and anti-aging effects

## Safety & unknowns

Endogenous molecule with a well-established safety profile. IV glutathione widely used in integrative medicine. Oral bioavailability is limited unless liposomal. Rare side effects: bloating (oral), mild discomfort (IV). Generally considered very safe. Widely available as a supplement.

## Studies

- Forman HJ, Zhang H, Rinna A. (2009). *Glutathione: overview of its protective roles, measurement, and biosynthesis*. Molecular Aspects of Medicine. Review. https://pubmed.ncbi.nlm.nih.gov/18796312/
  Review of glutathione biochemistry covering its antioxidant and detoxification roles, how it is measured, and how it is synthesized.
- Richie JP Jr, Nichenametla S, Neidig W, et al. (2015). *Randomized controlled trial of oral glutathione supplementation on body stores of glutathione*. European Journal of Nutrition. Clinical trial. https://pubmed.ncbi.nlm.nih.gov/24791752/
  6-month placebo-controlled RCT in which oral glutathione raised glutathione levels in blood and buccal cells in a dose- and time-dependent way; levels returned to baseline after a 1-month washout.

## Status sources

- [Richie et al. 2015 — RCT of oral glutathione supplementation](https://pubmed.ncbi.nlm.nih.gov/24791752/)
- [PubChem CID 124886 (glutathione)](https://pubchem.ncbi.nlm.nih.gov/compound/124886)
- [WADA 2026 Prohibited List (not named; IV infusions over 100 mL per 12 h are banned under M2.2 whatever they contain)](https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf)

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Educational reference only — not medical advice. No dosing information is published. Tiers rate the strength of published evidence, not effectiveness or safety.