Low Level of Supplemental Dietary L carnitine Increases Energy Expenditure in Overweight, But Not Lean, Cats Fed a Moderate Ener 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 LiquiCarn L Carnitine Deficiency in Cats PetMD What science says about L carnitine and Choline for cats Stylla