What is L Methionine? Benefits and Properties HSN Blog Amazon.com: Pure Encapsulations L Methionine Glutathione and Amino Acid Supplement for Joints, Liver and Pancreas Support, Antioxidants, and Nervous System* 60 Capsules : Health & Household Frontiers Pathological role of methionine in the initiation and progression of biliary atresia protein synthesis protein intake. you can eat a pound of steak and only ~32% of those amino acids actually become new protein in your body. the rest gets converted to glucose