Glutathione

Overview

Glutathione is an endogenous tripeptide (gamma-L-glutamyl-L-cysteinyl-glycine) that serves as the principal intracellular antioxidant in mammalian cells. It is not FDA-approved as a drug in the US; parenteral glutathione is used off-label (and in some compounding settings) for oxidative stress, hepatic support, and — controversially — skin lightening. The FDA has warned against injectable glutathione for skin lightening (2019) due to reports of serious adverse events.

Mechanism of Action

Glutathione cycles between reduced (GSH) and oxidized (GSSG) forms, donating electrons to reactive oxygen species via glutathione peroxidase. It serves as a cofactor for glutathione S-transferases (GSTs) in Phase II detoxification, maintains reduced protein thiols, supports T-cell proliferation and NK cell cytotoxicity, and regenerates vitamins C and E. Proposed skin-lightening activity is attributed to inhibition of tyrosinase and a shift from eumelanin toward phaeomelanin synthesis, though clinical evidence is limited and largely from small Asian dermatology trials.

Research Summary

A randomized, double-blind pilot trial (Hauser et al., Movement Disorders, 2009, PMID 19230029) tested IV glutathione 1,400 mg three times weekly for 4 weeks in Parkinson's disease (n=21); it was well tolerated but did NOT show a statistically significant effect on UPDRS scores. A large randomized trial of inhaled glutathione (646 mg every 12 hours for 6 months) in cystic fibrosis (Griese et al., Am J Respir Crit Care Med, 2013, PMID 23631796) did not demonstrate clinically relevant improvements in lung function, exacerbations, or quality of life. Oral glutathione has poor bioavailability due to GI degradation, driving investigation of IV, nebulized, liposomal, and sublingual delivery. The FDA issued a 2019 warning about compounded sterile injectable glutathione made from dietary-grade ingredient, citing adverse-event reports (including Stevens-Johnson syndrome, toxic epidermal necrolysis, and kidney dysfunction) particularly in the context of unregulated IV skin-lightening use.

Vendors selling Glutathione

Scored vendors carrying Glutathione, ranked by trust grade. Grades are computed from indexed Certificates of Analysis. Full $/mg pricing is on the comparison page.

Prescribers who offer Glutathione

96 prescribers in our directory work with Glutathione, each confirmed from their own website. Peptides like Glutathione require a prescription from a licensed provider.

Reported Side Effects

• Bloating and abdominal cramps (oral administration)
• Zinc depletion with prolonged high-dose use
• Bronchospasm (inhaled formulations)
• Severe cutaneous adverse reactions — Stevens-Johnson syndrome and toxic epidermal necrolysis — reported with unregulated injectable skin-lightening use (FDA 2019)
• Acute kidney injury, thyroid dysfunction, and hypersensitivity reactions reported with unregulated IV use
• Risk of infection / bloodborne pathogen transmission from non-sterile IV administration

Compare Glutathione with Others

Research References

• Randomized, double-blind, pilot evaluation of intravenous glutathione in Parkinson's disease (Hauser et al., Movement Disorders) (2009)
• Regulation of glutathione synthesis (Lu, Mol Aspects Med) (2009)
• Inhalation treatment with glutathione in patients with cystic fibrosis: a randomized clinical trial (Griese et al., Am J Respir Crit Care Med) (2013)
• FDA highlights concerns with using dietary ingredient glutathione to compound sterile injectables (2019)

Frequently asked questions

Has Glutathione been independently lab-tested?

Disclosed Labs has collected 66 Certificates of Analysis (COA) for Glutathione from 10 independent testing labs. 28 vendors have submitted material for testing. Products average 99.4% tested purity across the corpus. Full testing data is available at https://www.disclosedlabs.com/peptides/glutathione/testing.

What is the average purity of Glutathione on the market?

Based on 66 COAs analyzed by Disclosed Labs, Glutathione products average 99.4% (±0.7%) tested purity. Individual vendor results vary; see per-vendor COA data at https://www.disclosedlabs.com/peptides/glutathione/coas.

Which labs have tested Glutathione?

Independent labs that have tested Glutathione include: ILS Labs (Grade A). Full lab credibility grades and profiles are at https://www.disclosedlabs.com/labs.

Where can researchers source Glutathione?

8 vendors with Disclosed Labs trust grades currently list Glutathione, including Glacier Aminos, Ion Peptide, Sunrise Bioresearch. Compare live prices and lab-verified COAs at https://www.disclosedlabs.com/prices/glutathione.

Which prescribers offer Glutathione with a prescription?

96 prescribers in the Disclosed Labs directory work with Glutathione, each confirmed from their own website. Glutathione requires a prescription from a licensed provider. Browse them at https://www.disclosedlabs.com/prescribers?peptide=Glutathione.

How does Glutathione work?

Glutathione cycles between reduced (GSH) and oxidized (GSSG) forms, donating electrons to reactive oxygen species via glutathione peroxidase. It serves as a cofactor for glutathione S-transferases (GSTs) in Phase II detoxification, maintains reduced protein thiols, supports T-cell proliferation and NK cell cytotoxicity, and regenerates vitamins C and E. Proposed skin-lightening activity is attributed to inhibition of tyrosinase and a shift from eumelanin toward phaeomelanin synthesis, though clinical evidence is limited and largely from small Asian dermatology trials.

What does the research say about Glutathione?

A randomized, double-blind pilot trial (Hauser et al., Movement Disorders, 2009, PMID 19230029) tested IV glutathione 1,400 mg three times weekly for 4 weeks in Parkinson's disease (n=21); it was well tolerated but did NOT show a statistically significant effect on UPDRS scores. A large randomized trial of inhaled glutathione (646 mg every 12 hours for 6 months) in cystic fibrosis (Griese et al., Am J Respir Crit Care Med, 2013, PMID 23631796) did not demonstrate clinically relevant improvements in lung function, exacerbations, or quality of life. Oral glutathione has poor bioavailability due to GI degradation, driving investigation of IV, nebulized, liposomal, and sublingual delivery. The FDA issued a 2019 warning about compounded sterile injectable glutathione made from dietary-grade ingredient, citing adverse-event reports (including Stevens-Johnson syndrome, toxic epidermal necrolysis, and kidney dysfunction) particularly in the context of unregulated IV skin-lightening use.