Glutathione Explained: Reduced and Oxidised Forms and How to Verify a Batch

Glutathione is a tripeptide made of glutamate, cysteine and glycine, with a molecular mass of 307.32 Da. It exists in a reduced form (GSH) and an oxidized form (GSSG), and the difference between the two is the main thing a batch report has to show. This guide explains its structure, what the literature covers and how to verify a batch.

Key facts

• Type: Tripeptide (three amino acids); the reduced form is called GSH
• Sequence: γ-L-Glutamyl-L-cysteinyl-glycine (γ-Glu-Cys-Gly)
• Molecular formula: C10H17N3O6S
• Molecular mass: 307.32 Da (reduced form); 612.63 Da (oxidized form, GSSG)
• CAS number: 70-18-8
• Supplied as: lyophilized powder in a sealed vial

What is glutathione

Glutathione has an unusual bond: glutamate is linked to cysteine through its side-chain carboxyl group, a so-called gamma linkage, which protects the molecule from ordinary peptidases. The cysteine carries a free thiol group. When two molecules lose a hydrogen each, their thiol groups join through a disulfide bond and form glutathione disulfide (GSSG).

What the scientific literature covers

Glutathione is one of the most studied small molecules in biochemistry. Laboratory topics include:

• Cellular redox balance, measured as the ratio of GSH to GSSG
• Detoxification reactions catalyzed by glutathione S-transferases
• Oxidative stress models in cell culture
• Analytical methods for measuring reduced and oxidized glutathione

These are laboratory findings. CellMind supplies Glutathione for research purposes only, not for human use.

How identity and purity are verified

The main impurity in reduced glutathione is its own oxidized form. HPLC separates GSH from GSSG, and the report should state the purity of the reduced form. Mass spectrometry distinguishes the two clearly: 307.32 Da for GSH against 612.63 Da for GSSG. In solution GSH oxidizes in contact with air, so freshly prepared solutions matter. Both results must appear on the certificate of analysis (CoA) for the specific batch. Our CoA guide explains how to read one.

Checklist before buying Glutathione

• A CoA for the specific batch
• HPLC purity stated as a number, above 99%
• Reduced form (GSH, 307.32 Da) named on the report
• A clearly stated amount per vial (1000 mg)
• A batch number on the vial that matches the report

Common questions about Glutathione

What is the difference between GSH and GSSG?

GSH is reduced glutathione, a single molecule with a free thiol group (307.32 Da). GSSG is the oxidized form: two glutathione molecules joined by a disulfide bond (612.63 Da).

Is glutathione a peptide?

Yes. It is a tripeptide of glutamate, cysteine and glycine, with an unusual gamma linkage between glutamate and cysteine.

Why does a glutathione solution lose quality over time?

The thiol group reacts with oxygen and the reduced form turns into GSSG. Cool storage, protection from air and fresh preparation slow this down.

Storage and handling

Keep lyophilized vials in a cool, dark place. After reconstitution the solution should be refrigerated and used within the planned study period. Avoid repeated temperature changes: they are the most common cause of degradation that nobody notices until results stop matching.

CellMind Glutathione 1000mg

• 1000 mg of lyophilized powder per vial, sealed under inert conditions
• HPLC-tested by Janoshik Analytical, purity above 99%
• A CoA for the specific batch with every order

Product page for US orders: Glutathione 1000mg. Ordering and delivery: Where to buy Glutathione. Reports for current batches: Lab reports and CoA.

Sources

• Meister A., Anderson M.E. Annual Review of Biochemistry. 1983;52:711–760.