Frontiers Lcarnitine in metabolic dysfunction associated steatotic liver disease: mechanisms and therapeutic potential 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 Role of carnitine in disease Nutrition & Metabolism Springer Nature Link JCI l Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans Impaired brain function improved by l carnitine in patients with cirrhosis: evaluation using near infrared spectroscopy Scientific Reports