Serum L Carnitine Levels Are Associated With First Stroke in Chinese Adults With Hypertension Stroke Acetyl L Carnitine for Heart, Diabetes & Kidney Health Kidney Coach 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 Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis