What Is Glutathione?
Glutathione is a tripeptide of glutamate, cysteine and glycine, and unlike most compounds shelved beside it, it is not a synthetic analogue of anything. It is made by essentially every cell in the body and is present intracellularly at millimolar concentrations — among the most abundant small molecules in a cell.
Its defining structural feature is an unusual gamma peptide bond between glutamate and cysteine, which makes it resistant to the peptidases that would otherwise degrade a normal tripeptide. The cysteine residue carries the thiol group that does the chemistry.
How It Is Studied to Work
Research interest centres on redox balance. Reduced glutathione (GSH) donates an electron to neutralise reactive oxygen species, forming glutathione disulfide (GSSG); glutathione reductase then regenerates GSH using NADPH. The GSH:GSSG ratio is one of the standard readouts of cellular oxidative state.
Beyond that, it is studied as a cofactor for glutathione peroxidases and S-transferases, the latter conjugating glutathione to xenobiotics as a phase II detoxification step. Much of the published work therefore measures the ratio rather than the absolute quantity.
Evidence and Regulatory Status
Glutathione's biochemistry is thoroughly established; what remains contested is what exogenous administration achieves, because oral glutathione is largely hydrolysed in the gut and bioavailability is poor. That is precisely why much research examines precursors such as N-acetylcysteine instead.
Glutathione supplied for laboratory research holds no marketing authorisation as a medicine in the United Kingdom and is not approved for human or veterinary administration. Claims made for it in cosmetic and wellness markets, particularly around skin, are not supported by regulatory approval in the UK.
Research Handling and Quality
Reduced glutathione oxidises readily on exposure to air, which is the single most important handling consideration: an improperly stored sample drifts toward GSSG and the ratio being measured is then an artefact of storage rather than of the experiment.
Store lyophilised material cold, dry and dark, minimise headspace, and prepare solutions fresh where the protocol allows.
Frequently Asked Questions
Is glutathione a peptide?
What is the GSH:GSSG ratio?
Why is oral bioavailability considered poor?
How should glutathione be stored?
Related Guides
Products discussed in this guide are for research and laboratory use only. AllMyPeptides does not condone or support misuse of any research materials. Not for human or animal consumption.