Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis Can L Carnitine supplementation lead to liver dysfunction? Consensus JCI l Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans 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