Glutathione

also known as: GSH, γ-L-glutamyl-L-cysteinylglycine, gamma-glutamylcysteinylglycine, reduced glutathione, L-glutathione

A naturally-occurring tripeptide antioxidant central to cellular redox balance, widely used in injectable longevity and wellness protocols despite limited randomized evidence.

Produced endogenously by nearly every cell; marketed as an injectable or IV compound for detoxification, skin lightening, and antioxidant support — with a mechanism that is well-established biochemically but whose therapeutic benefits via exogenous administration remain contested.

Mechanism of action

Functions as the primary thiol-based redox buffer in cells. Its cysteine sulfhydryl group donates electrons to neutralize reactive oxygen species (ROS) and free radicals, becoming oxidized to GSSG in the process; GSSG is then recycled back to GSH by glutathione reductase using NADPH. Also serves as a substrate for glutathione S-transferases (GSTs) in Phase II detoxification, conjugating xenobiotics and heavy metals for excretion. Maintains the reduced state of other antioxidants including vitamins C and E, and is controlled transcriptionally by the Nrf2 pathway.

Primary uses

Injectable antioxidant and 'detox' wellness therapy
Adjunct treatment in acetaminophen toxicity (via N-acetylcysteine precursor pathway, clinically established)
Investigational for Parkinson's disease (small pilot trials)
Off-label skin lightening via injection (unregulated; safety concerns)
Nebulized forms investigated for pulmonary conditions

Typical dosing

100–2000 mg 1–3x weekly (IV, subcutaneous, or intramuscular)

Dosing varies enormously by practitioner and indication. Wellness IV protocols commonly use 600–2000 mg per infusion. Subcutaneous compounded protocols typically 100–300 mg per injection. No FDA-established dose.

Regulatory status

Not FDA-approved as a standalone injectable drug. Available via compounding pharmacies under 503A. Widely used off-label in IV and subcutaneous wellness protocols, particularly for skin lightening (notably in Southeast Asia), liver support, and general antioxidant therapy. In 2019, the FDA warned against compounded glutathione skin-lightening products due to safety concerns about unregulated sourcing.

References

[review] Santacroce G, et al. "Glutathione: Pharmacological aspects and implications for clinical use in non-alcoholic fatty liver disease." Front Med (Lausanne), 2023;10:1124275.
[review] Kalinina E, Novichkova M. "Glutathione in protein redox modulation through S-glutathionylation and S-nitrosylation." Molecules, 2021;26(2):435.
[pubmed] Kumar P, et al. "Glutathione, an antioxidant tripeptide: dual roles in carcinogenesis and chemoprevention." Curr Pharm Des, 2018;24(14):1524-1533. PMID: 30727890.

Related peptides

NAD+

An essential cellular coenzyme that declines with age; now heavily marketed in IV and injectable longevity protocols despite limited randomized clinical evidence for anti-aging claims.

Thymosin α1

The most clinically studied thymic peptide — approved in 35+ countries as Zadaxin for hepatitis B and C, with 30+ RCTs across more than 11,000 subjects. Not FDA-approved despite extensive global use.

SS-31 (Elamipretide)

The first FDA-approved mitochondria-targeted peptide therapeutic — approved September 2025 as Forzinity for Barth syndrome, with broader investigation in heart failure, macular degeneration, and aging.

Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.