S-Adenosyl-L-methionine (SAMe) exerts many key functions in the liver, including serving as a precursor for cysteine, 1 of 3 amino acids of glutathione–the major physiologic defense mechanism against oxidative stress. It has been well established that S-adenosyl-L-methionine (SAMe) is the principal methyl donor in methyltransferase reactions and that SAMe supplementation restores hepatic glutathione (GSH) deposits and attenuates liver injury.