S-Methylglutathione is primarily used in biochemical research to study the role of glutathione in cellular processes. It serves as a substrate or inhibitor in enzymatic studies, particularly those involving glutathione S-transferases, which play a crucial role in detoxification and metabolism. Researchers also utilize it to investigate the mechanisms of oxidative stress and cellular defense systems. Additionally, it is employed in the development of assays to measure enzyme activity and to explore the impact of methylation on glutathione-related pathways. Its applications extend to understanding the regulation of redox balance and the modulation of signaling pathways in various biological systems.