Glutathione

Glutathione (GSH) is a tripeptide, a chain of three amino acids: glutamate, cysteine and glycine (gamma-L-glutamyl-L-cysteinyl-glycine). The 'gamma' means the glutamate is linked through its side chain rather than its main chain. Cells make it themselves using two enzymes, glutamate cysteine ligase and glutathione synthetase, and it is the most abundant small sulphur-containing (thiol) molecule in cells (Lu, 2013). Its role in cell chemistry is well established from decades of cell, animal and human research. Trials giving glutathione to people are fewer, smaller and mixed. In healthy adults, a 4-week randomised trial of 40 people found no change in markers of oxidative stress or in glutathione status (Allen and Bradley, 2011), while a 6-month trial of 54 people reported higher glutathione levels in blood. Trials on skin colour are few and short (for example 60 people over four weeks), and a systematic review called that evidence inconclusive because of study quality and inconsistent results (Dilokthornsakul et al., 2019). A placebo-controlled trial in 45 people with Parkinson's disease found no difference from placebo. How much glutathione is absorbed intact, and its long-term safety, are not established. Supplied for laboratory research use only.