L-Glutathione — Reference, Dosing & Cited Studies

What it is

L-Glutathione is a naturally occurring tripeptide (glutamate–cysteine–glycine) found in every human cell, often called the master antioxidant. It protects cells from oxidative stress, supports liver detoxification, sustains a balanced immune response, contributes to healthy energy levels, and is closely tied to skin tone and clarity. Endogenous levels decline with age, stress, and environmental exposures, making support relevant for long-term wellness.

Mechanism of action

Reduced glutathione (GSH) directly scavenges reactive oxygen species and serves as the substrate for glutathione peroxidases, S-transferases, and reductases — central to xenobiotic conjugation in the liver and to redox homeostasis across tissues.

Half-life: Oral GSH has poor systemic bioavailability; IV/IM/inhaled or precursor (NAC, glycine) approaches are commonly used.

Evidence summary

Long line of biochemistry and aging research supports glutathione's central redox role. Human supplementation trials are mixed for oral GSH; IV and precursor approaches show clearer biomarker improvements.

Typical dosing protocols

Typical dose

50000–50000 mcg

Frequency

Every third day

Cycle length

4 weeks

200–600 mg IV or IM, 1–3× weekly
Cycles 6–12 weeks based on goals
Co-factor support: NAC, glycine, alpha-lipoic acid, B-vitamins

Side effects & safety

Generally well-tolerated; possible mild GI upset (oral) or sulphur taste (IV)
Rare hypersensitivity reactions reported with IV use
Caution with severe asthma (inhaled forms have triggered bronchospasm in case reports)

Cited studies

Disclaimer

All content is for research and educational purposes. Peptides described are sold for laboratory research use only and are not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before beginning any protocol.