Glutathione FAQ: Your Questions Answered
The questions below are the ones that come up specifically about Glutathione, rather than general peptide questions that apply to everything.
Overview
Common questions: reduced (GSH) versus oxidised (GSSG), why the vial is 1500 mg, why it smells slightly of sulfur, and why its unusual bond resists enzymes.
What Glutathione actually is
Glutathione is a very small peptide — just three building blocks, glutamate, cysteine and glycine — that nearly every cell makes for itself. Its sulfur group grabs reactive oxygen, which makes it the main built-in antioxidant researchers measure when they study oxidative stress. This is the reduced form, called GSH.
Supplied for laboratory research use only — not for human or animal use.
Third-party tested by HPLC and LC-MS, ≥99% purity, with a Certificate of Analysis available on request. Ships across Canada.
Technical detail below
Glutathione — common questions
Is this reduced (GSH) or oxidised (GSSG) glutathione?
Reduced glutathione, GSH. The oxidised form, GSSG, is two GSH molecules joined by a disulfide; it shows up as a slow degradation product if a solution is exposed to air, metals or alkaline pH.
Why is the glutamate linked through its side chain?
Glutathione's glutamate is attached through its γ-carboxyl group instead of the normal α-peptide bond. Most peptidases do not recognise that link, so the tripeptide resists ordinary protein-digesting enzymes; only γ-glutamyl transpeptidase cleaves it.
Why is the vial 1500 mg when most peptides here are 10 mg?
Glutathione is a small, inexpensive-to-make tripeptide and is typically worked with at milligram-per-millilitre strengths far higher than signalling peptides, so vials are filled by the hundreds of milligrams.
Why does my solution smell slightly of sulfur?
The free thiol on cysteine gives glutathione a faint sulfur odour. That is normal. A strong change in smell, colour or clarity is worth noting against the batch record.
Is glutathione an approved drug?
This product is not a medicine and is not approved for human or veterinary use. It is supplied strictly as a laboratory research material for in vitro work.
What Glutathione is studied for
Glutathione is the most abundant low-molecular-weight thiol in most cells, and the ratio of reduced to oxidised glutathione is widely used as a read-out of oxidative stress in cell-culture and tissue studies.
Meister and Anderson (Annu Rev Biochem 1983) reviewed glutathione synthesis by γ-glutamylcysteine synthetase and glutathione synthetase, and its breakdown by γ-glutamyl transpeptidase — the framework most synthesis and turnover studies still use.
GSTs conjugate glutathione to electrophilic compounds, and this conjugation step is a standard model in xenobiotic-metabolism research.
Glutathione peroxidases use GSH to reduce hydrogen peroxide and lipid hydroperoxides, with glutathione reductase recycling GSSG back to GSH using NADPH — a common model for studying peroxide handling in vitro.
Summarizes published preclinical literature — see the selected references below. Provided for research reference only; not a claim of efficacy or a description of human use.
References describe in-vitro and preclinical research and are listed for reference only — not evidence of efficacy and not a description of human use.
More Glutathione reference
Lyophilized and reconstituted storage conditions, plus the practical working window.
Diluent selection, dissolution behaviour, and the calculator preset for this compound.
Which solvents work, why, and what abnormal dissolution behaviour indicates.
The specific chemical routes by which this molecule breaks down, and how to limit each.
Which assays are informative for this molecule, and what to actually check on its COA.
Compound-specific bench practices, and the errors most often made with this molecule.
What to inspect on arrival, and which conditions actually warrant rejecting a vial.
FAQ reference for other compounds
Reviewed for research-use compliance by Kobi Williams, Founder — Popular Peptides Canada. Last reviewed 22 July 2026.
Glutathione is supplied strictly as a research chemical for in-vitro laboratory and research use only. It is not intended for human or animal consumption, diagnostic, or therapeutic use. This page is educational laboratory-handling reference information — not medical advice, not usage guidance, and not a protocol.