Glutathione (GSH) is a crucial intracellular peptide with multiple functions, including detoxification, antioxidant defense, maintenance of thiol status, and modulation of cell proliferation. GSH is synthesized in the cytosol of all mammalian cells through a tightly regulated process involving two key enzymes: glutamate cysteine ligase (GCL) and glutathione synthase (GS). GCL, composed of a catalytic (GCLC) and modifier (GCLM) subunit, is regulated at multiple levels, including transcriptional and post-transcriptional mechanisms. GSH synthase (GS) is also regulated in a coordinated manner, and its up-regulation can enhance the cell's capacity to synthesize GSH. Oxidative stress induces the expression of GSH synthetic enzymes, and key transcription factors involved include Nrf2/Nrf1 via the antioxidant response element (ARE), activator protein-1 (AP-1), and nuclear factor κ B (NFκB). Dysregulation of GSH synthesis is associated with various pathological conditions, such as diabetes mellitus, pulmonary fibrosis, cholestatic liver injury, endotoxemia, and drug-resistant tumor cells. The liver plays a central role in maintaining interorgan GSH homeostasis, and manipulation of GSH synthesis is an important therapeutic target in many disorders.Glutathione (GSH) is a crucial intracellular peptide with multiple functions, including detoxification, antioxidant defense, maintenance of thiol status, and modulation of cell proliferation. GSH is synthesized in the cytosol of all mammalian cells through a tightly regulated process involving two key enzymes: glutamate cysteine ligase (GCL) and glutathione synthase (GS). GCL, composed of a catalytic (GCLC) and modifier (GCLM) subunit, is regulated at multiple levels, including transcriptional and post-transcriptional mechanisms. GSH synthase (GS) is also regulated in a coordinated manner, and its up-regulation can enhance the cell's capacity to synthesize GSH. Oxidative stress induces the expression of GSH synthetic enzymes, and key transcription factors involved include Nrf2/Nrf1 via the antioxidant response element (ARE), activator protein-1 (AP-1), and nuclear factor κ B (NFκB). Dysregulation of GSH synthesis is associated with various pathological conditions, such as diabetes mellitus, pulmonary fibrosis, cholestatic liver injury, endotoxemia, and drug-resistant tumor cells. The liver plays a central role in maintaining interorgan GSH homeostasis, and manipulation of GSH synthesis is an important therapeutic target in many disorders.