Didn't another study show carnitine was good for the heart? 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 What is the role of carnitine (L carnitine) in the management of heart failure? JCI l Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans Primary carnitine deficiency cardiomyopathy International Journal of Cardiology