To date, GSH is mainly produced via fermentation
The characteristics of glutathione are the following: (a) discovered by Hopkins in 1921 [67], (b) synthesized intracellularly by glutamate-cysteine ligase and glutathione synthetase [68], (c) exists in reduced (GSH) and oxidized (GSSG) forms, maintaining cellular redox balance [69], (d) functions in melanogenesis inhibition through tyrosinase suppression and pheomelanin synthesis [70], and (e) oral bioavailability is enhanced through liposomal formulations, S -acetyl derivatives, or co-administration with precursors [71]
Neri S, Calvagno S, Mauceri B, Misseri M, Tsami A, Vecchio C, et al
Biochim Biophys Acta 1559:171178 Richman PG, Meister A (1975) Regulation of gamma-glutamycysteine synthetase b nonallosteric feedback inhibition by glutathione