Methionine must be ingested in the diet or as a supplement and is used for protein synthesis, including the formation of SAMe, L-homocysteine, L-cysteine, taurine, and sulfate. The first step in the conversion of methionine is to homocysteine and SAM. SAM is a methyl donor that is involved in many steps in lipid metabolism. SAM contributes to the formation of phosphatidylethanolamine and subsequently to phosphatidylcholine. Phosphatidylcholine is involved in producing very-low-density lipoproteins (VLDL). VLDLs prevent fat accumulation in the liver. SAM is also a methyl donor used to produce creatine. Creatine is a protein that helps muscle cells produce energy. Homocysteine is further modified to produce cysteine. Cysteine is a precursor of glutathione and taurine.