NaturesField L Carnitine Nature'sfield Online Pharmacy L carnitine is primarily synthesized in the liver from the amino acids lysine and methionine through a series of four enzymatic reactions, with the liver and kidneys converting the precursor butyrobetaine into active Pure Encapsulations Acetyl L Carnitine 500mg 60 Capsules Bahrain Hewyn GNC Total Lean L Carnitine 1000 Mg 60 Tablets (60 Servings)