Glutathione reductase is an enzyme () which reduces oxidized glutathione (GSSG) to the sulfhydryl form GSH. For every mole of GSSG one mole of NADPH is reqired. The NADPH is generated through the Pentose phosphate pathway. In cells exposed to high oxidizing stress, like erythrocytes, up to 10% of the glucose consumption may be used for production of the NADPH needed.

EC 1.8.1