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 with Chromium Wycoff Wellness JCI l Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans Pathobiological Relationship of Excessive Dietary Intake of Choline L Carnitine: A TMAO Precursor Associated Aggravation in Heart Failure in Sarcopenic Patients