L-Glutathione (GSH)

Reduced glutathione uses its thiol to reduce hydrogen peroxide and lipid peroxides, becoming the oxidized form, which reductase then regenerates with NADPH. Concentration is highest in the liver. The oral tripeptide is easily hydrolyzed in the gut; cells still mainly keep the pool by making it themselves.

Glutathione S-transferases attach this tripeptide to electrophilic metabolites and some drug intermediates, raising water solubility so they can leave in bile or urine. Hepatic phase-II detoxification follows this classic path; the γ-glutamyl bond helps it resist ordinary peptidases.

Glutathione keeps lymphocyte redox status, shaping T-cell proliferation and cytokine balance. Oral absorption is limited, yet human trials still watch oxidative-stress markers; people with recurring allergy or low-grade inflammation often match gaps on this immune-oxidative path, alongside detox uses.