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 Deficiency: What Is It, Causes, Symptoms, and More Osmosis L Carnitine in Mitochondria Encyclopedia MDPI Comparison of short term and long term effects of peroral L carnitine intake: clinical implications of elevated TMAO levels in cardiovascular complications