Glutathione

Glutathione (γ-Glu-Cys-Gly, GSH) is the body's master antioxidant tripeptide, present in essentially all cells and central to redox homeostasis, hepatic detoxification through Phase II conjugation reactions, and protection against oxidative stress. Unlike most compounds on Peptigrity, glutathione is endogenously produced and supplemented forms have a long history of medical and dietary supplement use. Various administration routes (oral, IV, inhaled, topical) have different bioavailability profiles and use cases.

What is glutathione and how does the antioxidant/detoxification mechanism work?

Glutathione is a tripeptide (γ-glutamyl-cysteinyl-glycine) functioning as the body's primary intracellular antioxidant and as a substrate for Phase II hepatic detoxification reactions (glutathione conjugation, glutathione peroxidase, glutathione transferases). Cellular glutathione levels are typically 1–10 mM, far higher than most other biological molecules, reflecting its central role in redox biology. Endogenous synthesis from cysteine, glutamate, and glycine occurs in essentially all cells.

Evidence level: established biochemistry; clinical use in hepatology, dermatology, and toxicology; human RCT for various indications

What does the research show for glutathione?

Established clinical uses include acetaminophen overdose treatment (via N-acetylcysteine, a glutathione precursor), chemotherapy support, and various hepatic disease indications. Topical glutathione is studied for skin pigmentation; IV glutathione is used clinically and through wellness clinics for varied indications including liver support, oxidative stress, and Parkinson's disease research. Single-dose pharmacokinetic studies found that oral glutathione has poor systemic bioavailability, because gut peptidases and enterocytes degrade much of an ingested dose before intact GSH reaches the circulation. Sustained daily dosing tells a different story: a 6-month randomized, double-blind, placebo-controlled trial (n=54) found that oral glutathione raised body stores of GSH — at 1,000 mg/day, erythrocyte, plasma and lymphocyte GSH rose about 30–35%, with a smaller increase (17% in blood) at 250 mg/day. Whether intact glutathione is absorbed or its constituent amino acids drive the rise in stores remains debated.; liposomal and other formulation strategies attempt to address this.

Source: Randomized controlled trial of oral glutathione supplementation on body stores of glutathione, Richie J.P. Jr., Nichenametla S., Neidig W., Calcagnotto A., Haley J.S., Schell T.D., Muscat J.E., Eur J Nutr, 2015 · Evidence level: substantial human clinical data across hepatic and toxicological indications; varied evidence quality for non-approved uses (skin pigmentation, wellness IV)

How does glutathione compare to other antioxidant compounds?

Glutathione is the body's primary endogenous antioxidant system, distinguished from supplemental antioxidants by its central biochemical role rather than a single-mechanism niche.

What are the documented side effects of glutathione?

Glutathione has an extremely favorable safety profile — endogenous production at 1–10 mM cellular concentrations means supplemental administration adds to a vast existing pool. IV administration may produce transient flushing, headache, or mild hypotension during infusion; oral administration is generally well-tolerated but has poor bioavailability. The most clinically relevant safety consideration is in patients with G6PD deficiency, where altered redox balance can have complex effects.

Evidence level: extensive clinical use; established safety profile across routes

What is the regulatory status of glutathione?

Glutathione is widely available as a dietary supplement in oral form in most jurisdictions, and IV glutathione is administered clinically in approved hospital and outpatient settings. Glutathione is not FDA-approved as a stand-alone therapeutic for any specific indication, but is incorporated into multiple approved clinical protocols (e.g., glutathione synthesis support through NAC for acetaminophen overdose). IV glutathione for skin lightening or general wellness purposes operates as medical service in many jurisdictions but is not FDA-evaluated for those uses. Regulatory context in are peptides legal regulatory status by country.

Why does glutathione vendor verification matter?

Glutathione is widely available across pharmaceutical, medical, and research-grade supply chains, with substantial quality variance — particularly between pharmacy-grade IV preparations and research-grade injectable material. Some "glutathione" products in non-pharmaceutical supply chains may contain oxidized glutathione (GSSG) rather than the active reduced form (GSH), or may be substantially degraded. Independent third-party testing including HPLC and verification of reduced-vs-oxidized state is essential for injectable use. Guidance in how-to-test-peptides hub.

How does Peptigrity verify glutathione vendors?

Peptigrity collects independent third-party Certificates of Analysis for glutathione from shops' official channels and verifies each for authenticity before publishing. Because shops choose which COAs to publish, results reflect the batches shops have made public rather than every production batch — a selection bias we state openly. A community-funded Testing Grant to purchase and test vials anonymously is in development. Tests in the database come from independent labs such as Janoshik Analytical, Freedom Diagnostics, and Chromate. Verification of the reduced (GSH) versus oxidized (GSSG) state is particularly important for this compound.

Frequently asked questions

What does glutathione do?

Glutathione is the body's master antioxidant tripeptide, central to intracellular redox homeostasis, hepatic Phase II detoxification, and protection against oxidative stress. It is endogenously produced in essentially all cells at high concentrations and has established clinical uses in hepatology and toxicology.

Is glutathione legal to purchase?

Glutathione is widely legal — available as a dietary supplement in oral form in most jurisdictions and administered IV in approved medical settings. Research-grade injectable glutathione is sold by third-party laboratories for laboratory use. Country breakdown in peptide legal status guide.

Does oral glutathione work?

Single-dose studies show oral glutathione has poor systemic bioavailability, because gut peptidases degrade much of it before it reaches the bloodstream. But sustained supplementation can still raise body stores: a 6-month randomized, double-blind, placebo-controlled trial (n=54) found daily oral glutathione increased GSH in erythrocytes, plasma and lymphocytes by roughly 30–35% at 1,000 mg/day (17% in blood at 250 mg/day), so chronic dosing can lift glutathione levels even though acute absorption of the intact tripeptide is low. Liposomal and other formulation strategies attempt to improve absorption, with varied evidence quality. Cellular glutathione levels respond more reliably to supplementation with precursors like N-acetylcysteine (NAC) or whey-derived cysteine sources than to direct oral glutathione.

Source: Randomized controlled trial of oral glutathione supplementation on body stores of glutathione, Richie J.P. Jr., Nichenametla S., Neidig W., Calcagnotto A., Haley J.S., Schell T.D., Muscat J.E., Eur J Nutr, 2015

Is IV glutathione safe?

IV glutathione has an extensive clinical safety record in approved medical settings — mild transient effects during infusion are common but serious adverse events are rare. The safety profile in non-medical wellness IV settings depends on practitioner training and product quality. G6PD deficiency is a notable consideration.

How can I verify a glutathione vendor is selling real product?

Independent third-party HPLC certificate of analysis from a lab the vendor does not own or pay, with verification of reduced (GSH) versus oxidized (GSSG) state. Mass spectrometry identity confirmation is essential. COA interpretation in red flags in peptide certificates of analysis.

Does Peptigrity recommend a glutathione dose?

No. Peptigrity is an independent review platform, not a medical authority. Clinical and supplement dosing varies widely by indication and route. Anyone considering use should consult a licensed physician.

This section is for educational and informational purposes only and does not constitute medical advice. Glutathione is the body's endogenous master antioxidant and is widely available across supplement, clinical, and research supply chains; specific therapeutic indications require physician evaluation. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.