How Long Does Glutathione Last? Shelf Life & Stability
"Stable" is meaningless without saying stable against what. Glutathione has its own set of degradation routes, and they determine which storage precautions actually matter for it.
Overview
Its weak point is the sulfur group. Air, trace metals like copper or iron, and higher pH slowly pair two molecules into oxidised glutathione (GSSG). Cold, slightly acidic and low-air keeps it in the reduced form.
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.
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Technical detail below
Degradation routes specific to Glutathione
- Oxidation of the cysteine thiol to glutathione disulfide (GSSG, about 612.6 Da), catalysed by trace Cu²⁺/Fe³⁺ and faster at neutral-to-alkaline pH.
- Mixed-disulfide formation with other thiols present in the solution.
- Further oxidation of the sulfur to sulfinic/sulfonic acid under harsh oxidising conditions.
The one chemistry to protect is the free thiol. Keep solutions cold, slightly acidic and low in oxygen, and use metal-free (or EDTA-containing) buffers where the protocol allows.
Freeze–thaw tolerance
Tolerates a few freeze-thaw cycles, but each thaw exposes the thiol to dissolved oxygen. Aliquot once and thaw each portion only once.
How storage addresses these routes
Practical window once reconstituted: about 1 week at 2-8 °C; frozen aliquots keep longer. Not strongly light-sensitive, but oxygen-sensitive: minimise headspace and avoid metal spatulas or metal-contaminated buffers.
Full Glutathione storage conditionsWhat 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.
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.
Questions specific to this compound — structure, chemistry, and common misconceptions.
Stability 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.