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 Carnitine palmitoyltransferase 1 facilitates fatty acid oxidation in a non cell autonomous manner: Cell Reports Fatty Acid Metabolism Concise Medical Knowledge Frontiers Fatty acid oxidation in immune function Carnitine Metabolism and Its Role in Fatty Acid Oxidation Creative Proteomics