Primary carnitine deficiency cardiomyopathy International Journal of Cardiology What is the role of carnitine (L carnitine) in the management of heart failure? 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 L Carnitine Is It Good or Bad for your Heart? Hammer Nutrition JCI l Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans