Glutathione Protocol

Dosing & Research

Last Updated: September 4, 2026

Also known as: GSH, L-Glutathione, Reduced Glutathione, Gamma-Glutamylcysteinylglycine, γ-L-Glutamyl-L-cysteinyl-glycine

Chemical Identity

Amino Acid Sequence: γ-Glu-Cys-Gly (γ-glutamyl-cysteinyl-glycine)
Molecular Formula: C10H17N3O6S
Molecular Weight: 307.32 g/mol
CAS Number: 70-18-8

Reduction of oxidative stress markers, Increased body glutathione stores (oral RCTs), Liver detoxification support, Immune function support, Skin brightening and melasma research (topical and oral), Longevity and mitochondrial support

Evidence Level

Human Clinical Data Available

Species Studied

Human • Animal • In vitro

Half-Life

Short systemic half-life (~14 minutes); route-dependent

Administration

• Oral
• Subcutaneous
• Topical

Frequency

Daily (oral); 2-3x weekly (subcutaneous); per clinical protocol (IV)

How It Works

Direct free-radical and ROS scavenging
maintains cellular redox balance (GSH/GSSG ratio)
regenerates other antioxidants (vitamins C and E)
supports Phase II detoxification (conjugation of toxins/xenobiotics)
cofactor for glutathione peroxidase and related enzymes

Dosing Structure

Dose

250–1,000 mg daily

Frequency

Daily (oral); 2-3x weekly (subcutaneous); per clinical protocol (IV)

Notes

Oral: 250-1,000 mg/day (common study doses; a 6-month RCT reported 17-35% increases in glutathione stores, Richie et al. 2015, PMID: 24791752). Subcutaneous (research use): 150-500 mg, 2-3x weekly. IV (clinical settings only): higher ranges reported, 600-2,000 mg. Topical: 0.5% formulations studied for skin brightening/melasma. Reduced oral glutathione bioavailability is debated; liposomal or S-acetyl-glutathione forms, or precursors such as NAC or GlyNAC, are frequently discussed alternatives. Reconstitution: lyophilized powder preferred for research; pH-sensitive (best ~5.5-7.0) with oxidation risk once reconstituted; protect from air and light, refrigerate, and use promptly. Generally well tolerated at studied oral doses; mild GI effects possible; IV forms carry a higher reported risk profile in some literature. For research and laboratory reference only -- no medical claims.

Example Protocols

Dose: 250–1,000 mg daily

Frequency: Daily (oral); 2-3x weekly (subcutaneous); per clinical protocol (IV)

Duration: Ongoing; studied over 6 months in oral RCTs

Off Period: Not listed

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Protocol Notes

•

Oral: 250-1,000 mg/day (common study doses; a 6-month RCT reported 17-35% increases in glutathione stores, Richie et al.

•

2015, PMID: 24791752).

•

Subcutaneous (research use): 150-500 mg, 2-3x weekly.

•

IV (clinical settings only): higher ranges reported, 600-2,000 mg.

•

Topical: 0.5% formulations studied for skin brightening/melasma.

•

Reduced oral glutathione bioavailability is debated; liposomal or S-acetyl-glutathione forms, or precursors such as NAC or GlyNAC, are frequently discussed alternatives.

•

Reconstitution: lyophilized powder preferred for research; pH-sensitive (best ~5.5-7.0) with oxidation risk once reconstituted; protect from air and light, refrigerate, and use promptly.

•

Generally well tolerated at studied oral doses; mild GI effects possible; IV forms carry a higher reported risk profile in some literature.

•

For research and laboratory reference only -- no medical claims.

What Is Glutathione?

Glutathione (GSH) is a naturally occurring tripeptide (glutamate-cysteine-glycine) and the most abundant intracellular thiol in mammalian cells, often described as the body's 'master antioxidant.' It is essential for detoxification, immune function, cellular protection, and redox homeostasis, and is extensively studied with strong mechanistic understanding and substantial clinical evidence. Endogenous levels decline with age, chronic stress, and toxin exposure.

Research Observations - Not Medical Claims

▸Body stores: A 6-month randomized, placebo-controlled trial of oral glutathione supplementation (500mg or 1,000mg/day) in healthy adults produced dose-dependent increases in blood, plasma, lymphocyte, and buccal cell glutathione levels of approximately 17–35% (Richie JP et al., 2015; PMID: 24791752).
▸Redox balance: GSH is the primary determinant of the intracellular GSH/GSSG (reduced/oxidized) ratio, the standard research marker of cellular oxidative stress.
▸Detoxification: Functions as the principal substrate for Phase II conjugation reactions, supporting hepatic clearance of xenobiotics and reactive metabolites.
▸Immune support: Adequate intracellular glutathione is associated with optimal lymphocyte and natural killer (NK) cell function in the immune research literature.
▸Skin pigmentation: Oral and topical glutathione have been studied for skin-brightening and melasma applications, with proposed anti-melanogenic (tyrosinase-inhibiting) activity.
▸Bioavailability: Oral bioavailability of reduced (free) glutathione is debated due to intestinal breakdown; liposomal and S-acetyl-glutathione formulations, and precursors such as NAC and glycine + NAC (GlyNAC), are commonly discussed alternatives in the research literature.

Evidence Summary

Human Clinical Data AvailableNaturally occurring endogenous tripeptide; sold as an oral supplement and used in various clinical/IV settings -- for research and laboratory reference only

Evidence StrengthStrong