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 Acetyl L Carnitine (ALCAR) Supplement for Horses Mad Barn History of L carnitine: Implications for renal disease Journal of Renal Nutrition Natural Factors Acetyl L Carnitine Mithaly.sa