Glutathione Explained: The Cell's Master Antioxidant

Glutathione is a tripeptide that almost every cell makes for itself. It is central to oxidative-stress biology, which is why it appears in so many research catalogues.

What glutathione is

Glutathione (GSH) is made of three amino acids: glutamate, cysteine and glycine. It has an unusual bond: the glutamate is linked through its side chain (a gamma-peptide bond), which protects glutathione from most peptidases.

The cysteine's thiol (–SH) group is the active part of the molecule.

The redox cycle

1. Reduced glutathione (GSH) donates electrons to neutralise reactive oxygen species, often via glutathione peroxidase enzymes.
2. Two GSH molecules become oxidised glutathione (GSSG), joined by a disulphide bond.
3. Glutathione reductase uses NADPH to convert GSSG back to GSH.

The GSH:GSSG ratio is one of the most widely used measures of a cell's redox state.

Detoxification

Glutathione S-transferases (GSTs) attach glutathione to reactive chemicals (electrophiles), marking them for export and removal. This "phase II conjugation" is a major research topic in toxicology and drug metabolism.

Why precursors are studied

Cells build glutathione inside themselves, and the supply of cysteine usually limits how fast they can do it. That is why precursors are a research theme:

• N-acetylcysteine (NAC) supplies cysteine.
• GlyNAC combines glycine with NAC.

Research compares supplying glutathione directly with supplying its building blocks, because whole glutathione is poorly absorbed through some routes and gets broken down outside cells.

Related reading

Glutathione recycling depends on NADPH, which links it to the wider NAD+ biochemistry of the cell.

Comparing glutathione listings

1. Reduced vs oxidised. Make sure the listing specifies reduced glutathione (GSH) if that's what you need.
2. Stability. GSH oxidises in solution and air, so storage and shipping conditions matter. See how research peptides are stored.
3. Compare price per mg on our glutathione comparison page. It is often sold in large quantities.

Summary

Glutathione is the main thiol antioxidant in cells. It is recycled through the GSH/GSSG cycle and used in detoxification reactions. PeptideCompare provides no dosing or usage guidance, and nothing here is for human or veterinary use.