Glutathione

The research profile.

Glutathione is the tripeptide gamma-L-glutamyl-L-cysteinyl-glycine, present in most mammalian cells at millimolar concentrations. Its unusual gamma-linkage between glutamate and cysteine makes it resistant to ordinary peptidases, and the reactive thiol on its cysteine residue is the chemical basis of everything it does. It is synthesised intracellularly in two ATP-dependent steps, so it is a metabolite rather than a signalling peptide.

The reduced form (GSH) donates electrons and is oxidised to the disulfide dimer GSSG, which glutathione reductase recycles using NADPH. The ratio between the two forms is used throughout the literature as a marker of cellular redox state. Glutathione also serves as the cosubstrate for the glutathione S-transferase family in phase II conjugation reactions and for glutathione peroxidase in peroxide reduction — the biochemistry set out in Meister's foundational review.

Because oral glutathione is largely broken down and reassembled from its constituent amino acids, the clinical literature is split. Intravenous and intramuscular protocols were used in the Parkinson's disease trials that account for most of the parenteral dosing data, while oral supplementation trials measured body stores and oxidative-stress biomarkers with mixed results — one crossover trial reporting no change in the biomarkers assessed. That heterogeneity is the central caveat when interpreting this compound.

For research purposes only. Not for human consumption, diagnosis, treatment, or prevention of any condition.

Categorised as Longevity — Compounds for cellular-ageing and immune research.