What is glutathione?
Glutathione is a tripeptide composed of glutamate, cysteine and glycine, supplied as a reference standard for laboratory research.
Glutathione structure and the gamma linkage
Its defining structural feature is the gamma peptide bond between the glutamate side chain carboxyl and cysteine, rather than the alpha linkage found in conventional peptides. That linkage is what distinguishes it structurally from an ordinary Glu-Cys-Gly tripeptide.
The free thiol group
The cysteine residue carries a free thiol, which is readily oxidisable. This is the single most important practical consideration in handling and storing the material, and it is covered in the storage and handling tab.
Specification figures for glutathione
The sequence, molecular formula and molecular weight for the lot supplied are stated on its certificate of analysis. Published figures for research compounds are not always consistent between sources, so this page defers to the certificate rather than restating a value that may not match the material in the vial.
Reduced and oxidised forms
Glutathione exists in a reduced form (GSH), carrying the free thiol, and an oxidised dimer (GSSG) in which two molecules are joined by a disulfide bond. These are different substances with different molecular weights. The form supplied is stated on the certificate of analysis for the lot, and it should be confirmed rather than assumed, since the ratio between the two is itself a common analytical measurement.
Analysis and certification
Each lot of glutathione is analysed by an independent laboratory before release. The certificate of analysis is published against the lot number rather than the product page, so the document you read is the document for the vial you receive.
Research use only
NH Peptides supplies glutathione as an analytical reference standard for laboratory research. It is not a food, food ingredient, food supplement or novel food, it is not supplied for any use in humans or animals, and no information on this page describes or implies any such use.
Purity specification for Glutathione
Lots are released against a ≥99% purity specification, determined by RP-HPLC peak area. The figure for the lot you receive is stated on its certificate of analysis and may differ from the specification.
A specification is a release threshold, not a description of every lot. Where a measured figure and the specification differ, the certificate is the record that applies to your material. Analytical figures relate to the lot they are published against and carry no implication of suitability for any purpose beyond laboratory research.
| Compound |
Glutathione, reduced |
| Also known as |
GSH |
| Class |
Tripeptide thiol |
| Amino acids |
3 |
| Linkage |
Gamma peptide bond at the glutamate side chain |
| CAS number |
Stated on the certificate of analysis |
| Molecular formula |
Stated on the certificate of analysis |
| Molecular weight |
Stated on the certificate of analysis |
| Appearance |
Stated on the certificate of analysis |
| Purity specification |
≥99% |
| Identity method |
LC-MS |
| Purity method |
RP-HPLC |
| Labelled quantity |
1500mg |
How Glutathione is tested
Two separate analyses are carried out on every lot before it is released, and both appear on the certificate.
RP-HPLC, for purity
Reversed phase high performance liquid chromatography separates the material by hydrophobicity. The main peak is integrated against the total peak area to give the purity figure. This is what the ≥99% specification refers to, and it is a measure of how much of the material is the intended compound rather than related substances, residual reagents or truncated sequences.
LC-MS, for identity
Liquid chromatography coupled to mass spectrometry confirms that the material eluting in the main peak has the expected mass. Purity alone does not establish identity: a lot can be 99% pure and still be the wrong compound. The two analyses answer different questions and both are needed.
What arrives with the order
- The vial, labelled with compound, labelled quantity and lot number
- A dispatch note listing the lot numbers supplied
- A storage and handling sheet
- The certificate of analysis for the lot, published against the lot number
If any of these is missing, or if the lot number on the vial does not match the certificate, contact us before using the material.
Storing glutathione
Store the sealed vial dry at −20°C or below, protected from light, moisture and air. Return to freezer storage on arrival and keep the vial sealed between uses.
Preparing glutathione solutions
The free thiol group oxidises readily on exposure to air and in solution. Prepare solutions immediately before use, minimise headspace and air exposure, and do not store prepared solutions for extended periods.
Oxidation will affect analytical results before it is visible, so do not rely on appearance as an indicator of condition.
Handling and disposal
Assess the hazards of this material before handling and use appropriate controls and protective equipment. Dispose of unused material, vials and packaging lawfully and in line with your institution’s waste procedures.
On receipt
Check the parcel before putting the material away. Three things are worth two minutes:
- Packaging integrity. Confirm the vial is intact, the seal is unbroken and the insulated packaging has not failed in transit.
- Lot number. Check the number on the vial label against the certificate of analysis and against the dispatch note. All three should agree.
- Return to storage. Move the material into its stated storage conditions promptly rather than leaving it at ambient temperature.
If anything does not match, or the packaging has clearly failed, contact us before using the material. Problems visible on arrival should be reported within 7 days so a carrier claim remains possible.
Record keeping
Record the lot number in your notes at the point of first use, alongside the date the vial was opened and the concentration of any stock solution prepared. Certificates are published against the lot number rather than the product, so the lot number is the only reliable link between your results and the analytical data for the material that produced them.
That link matters later. If a question arises about a result months after the work, the lot number is what makes the material traceable and the work auditable.