Reduced glutathione (GSH)

Glutathione in Canada

Also known as GSH · Reduced glutathione · L-Glutathione · γ-Glutamylcysteinylglycine · Tationil

Glutathione is the tripeptide γ-L-glutamyl-L-cysteinyl-glycine — the most abundant non-protein thiol in mammalian cells and the molecule most of the body's redox buffering runs through. Unlike almost everything else in this catalogue it is an endogenous compound with a large biochemistry literature behind it; the open questions are about exogenous administration, where the evidence on oral, intravenous and intranasal routes is small, mixed and often uncontrolled. Canada Peptides carries research-grade reduced glutathione as a 600 mg lyophilised vial, priced and shipped in CAD for laboratory and research use only.

Quick facts

Class: Endogenous tripeptide thiol (non-ribosomal)
Structure: 3 amino acids · γ-Glu-Cys-Gly · C10H17N3O6S · ~307 Da; reduced (GSH) and oxidised dimer (GSSG) forms
Half-life: Roughly 10–15 minutes in plasma after intravenous administration in humans; intracellular turnover is hours to days
Route in research: Intravenous, intramuscular, oral, liposomal oral, intranasal and inhaled in published studies
Cadence in research: From twice daily to three times weekly in trials, depending on route
Storage: Lyophilised: refrigerated, dark, dry. Reconstituted: refrigerated, air excluded, used promptly — the thiol oxidises in solution
Status in Canada

Pharmacology

Glutathione's pharmacology is really the pharmacology of the glutathione system. Intracellularly it cycles between the reduced form (GSH) and the oxidised disulfide dimer (GSSG); glutathione peroxidases consume GSH to reduce hydrogen peroxide and lipid peroxides, and glutathione reductase regenerates GSH from GSSG using NADPH. The GSH:GSSG ratio — normally well above 100:1 in cytosol — is one of the standard laboratory measures of oxidative stress, which is why the compound sits next to NAD+ in the redox literature: NADPH derived from the same nucleotide pool is what keeps the cycle turning.

Synthesis is the rate-limiting variable. Glutamate–cysteine ligase forms the unusual γ-glutamyl bond between glutamate and cysteine, and glutathione synthetase adds glycine. Cysteine availability limits the first step, which is why N-acetylcysteine — a cysteine prodrug — is the clinically established way to restore glutathione in paracetamol toxicity, and why some argue that precursors are a more rational route than the tripeptide itself.

Exogenous pharmacokinetics are unfavourable for a simple "top-up" model. After intravenous administration in healthy volunteers, plasma glutathione rose sharply and then fell with a half-life on the order of 10–15 minutes as it was hydrolysed by γ-glutamyl transpeptidase on cell surfaces and cleared by the kidney; the constituent amino acids, especially cysteine, rose for longer. Orally, the same enzyme in the intestinal brush border and the liver breaks most of a dose into amino acids before it reaches the systemic circulation, which is the basis of the bioavailability argument. Proponents of oral supplementation argue that the amino acids are then reassembled intracellularly; sceptics point out that this is indistinguishable from eating protein.

Intranasal delivery was studied specifically to bypass first-pass metabolism, and magnetic-resonance spectroscopy in the 2017 Parkinson's work did detect a rise in brain glutathione signal after dosing. That is a pharmacokinetic finding, not a clinical one.

Glutathione FAQ

Is Glutathione for sale in Canada?

Yes. Research-grade reduced glutathione is available in Canada from Canada Peptides as a 600 mg lyophilised vial, priced and shipped in CAD. It is supplied strictly for laboratory and research use, not for human consumption.

What is glutathione?

Glutathione is a tripeptide of glutamate, cysteine and glycine made in every cell of the body. It is the principal intracellular antioxidant and the substrate the liver uses to conjugate and excrete many toxins and drug metabolites. Its biochemistry is well established; the effect of taking it from outside the body is not.

Is glutathione a peptide?

Technically yes — it is three amino acids joined by peptide bonds — but it is not made on a ribosome and its glutamate is linked through an unusual γ-carboxyl bond, which is why ordinary peptidases cannot break it down. Chemically it behaves more like a small thiol than like the synthetic peptides in this catalogue.

What is the half-life of glutathione?

Short in plasma: after intravenous administration in healthy volunteers, plasma glutathione fell with a half-life of roughly 10–15 minutes as it was broken down by γ-glutamyl transpeptidase and cleared by the kidney. Inside cells it turns over on a scale of hours to days.

Does oral glutathione work?

The evidence conflicts. A 1992 study found a 3 g oral dose did not raise plasma glutathione; a 2015 six-month trial found 250–1,000 mg daily did raise glutathione in blood and buccal cells; a 2011 four-week study found no change in oxidative-stress markers. Liposomal formulations have reported better uptake in one trial. The question is not settled.

How was glutathione dosed in studies?

It depends on route. IV Parkinson's trials used 600 mg twice daily or 1,400 mg three times weekly; oral trials used 250–1,000 mg daily; intranasal studies used 300–600 mg daily. None of these is a validated dose for any purpose, and this page does not recommend one; the material sold here is for research use only.

What are the safety concerns with glutathione injections?

Controlled trials report good tolerability at the doses studied. The concerning reports come from unregulated intravenous use for skin lightening, which has drawn a 2011 Philippine FDA advisory describing serious skin, thyroid and kidney adverse events, and from a 2019 U.S. FDA alert about compounded injections made with endotoxin-contaminated material. No injectable glutathione is approved in Canada.

Is glutathione legal in Canada?

Oral glutathione is a licensed natural health product ingredient in Canada and products carrying an NPN are sold legally. No injectable glutathione has a DIN or market authorisation. Research-grade material may be sold for laboratory research, which is how it is sold here. It is not on the WADA Prohibited List.

Glutathione in Canada

Quick facts

Glutathione — for sale in Canada

What is Glutathione?

Evidence at a glance

Pharmacology

Identity and chemistry

Storage and stability

Research indications

Research protocols

Interactions and stacking in research

Reconstitution and handling

Side effects and safety signals

Regulatory status in Canada

Further reading

Glutathione FAQ

Research references