6 potential benefits of l carnitine Good Food When to take L carnitine: Dosage, forms, and side effects L carnitine promotes liver regeneration after hepatectomy by enhancing lipid metabolism Journal of Translational Medicine Springer Nature Link 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 Some supplements may cause liver damage