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 Revisiting the Role of Carnitine in Heart Disease Through the Lens of the Gut Microbiota TMAO: how gut microbiota contributes to heart failure Translational Research Acetyl L Carnitine for Heart, Diabetes & Kidney Health Kidney Coach