Research library / Compounds

What is ?

Three amino acids with an unusual bond, and the most abundant small thiol inside cells.

is a tripeptide made from glutamate, cysteine and glycine. It is the most abundant low-molecular-weight thiol in cells, where it helps maintain redox balance and reacts with oxidants and electrophiles. Prism Labs supplies it as a 600 mg lyophilized vial.

Prism Labs editorial · Updated September 10, 2026 · 3 min read

Lyophilized vial600mg · 99.11% purity$34.99View product

What it is

Its full chemical name is γ-L-glutamyl-L-cysteinylglycine. The reference record lists the formula C10H17N3O6S and a molecular weight of 307.33 g/mol (PubChem CID 124886).

The γ (gamma) is the unusual part. Glutamate is joined to cysteine through its side-chain carboxyl group instead of the usual backbone one, so the first link is not a standard peptide bond.

The thiol (–SH) group on cysteine does the chemical work, which is why the reduced form is abbreviated GSH.

Sources: [1] PubChem · reference structure · [2] Molecular Aspects of Medicine · 2009

Reduced and oxidized: GSH and GSSG

Two GSH molecules can give up electrons and join through a disulfide bond, forming the oxidized form, GSSG.

The ratio of GSH to GSSG is a common measure of a sample’s redox state. A 1969 enzymatic method for measuring the total and oxidized forms is still widely cited; chromatography and mass spectrometry are now used as well.

Research material is labeled as the reduced or oxidized form, and the identity result on the COA confirms which one a lot contains.

Sources: [2] Molecular Aspects of Medicine · 2009 · [3] Analytical Biochemistry · 1969 · [4] Journal of Chromatography B · 2009

Lyophilized vial from Prism Labs — Every lot ships with its own certificate of analysis.

How cells make it

Cells build it from its three amino acids in two enzyme-driven steps and recycle GSSG back to GSH. A 2009 overview and a 2024 review describe the synthesis and how it is regulated.

The 2024 review also notes a quieter job: it serves as a store of cysteine.

Sources: [2] Molecular Aspects of Medicine · 2009 · [5] Current Medicinal Chemistry · 2024

What researchers have studied

The literature is enormous. Main laboratory themes:

Protection of cells against oxidants and reactive electrophiles.
Redox balance, with the GSH/GSSG ratio as a marker.
Detoxification reactions in which it is attached to foreign compounds.
Measurement methods, from enzymatic assays to mass spectrometry.

These are observations in laboratory models. They are not evidence about any use in people.

Sources: [2] Molecular Aspects of Medicine · 2009 · [5] Current Medicinal Chemistry · 2024 · [3] Analytical Biochemistry · 1969 · [4] Journal of Chromatography B · 2009

How it is supplied and stored

ships as a lyophilized (freeze-dried) powder in 600 mg vials. The powder is stable at room temperature in transit. For lab use it is reconstituted with bacteriostatic water such as .

Concentration is content divided by volume: 600 mg in 6 mL gives 100 mg per mL. The reconstitution calculator handles other combinations.

For storage before and after reconstitution, see how to store lyophilized peptides.

How to verify a batch

Every lot has its own certificate of analysis from an independent lab. Read three results separately:

Identity: confirms the expected compound was detected.
Purity: the share of the measured material that is the intended compound.
Content: the amount measured, compared with the label.

Then match the lot number on your vial or bottle to the report, and use the report’s verification link to confirm it with the testing lab. Step by step: how to read a peptide COA.