L Carnitine Supplement: Heart Concerns Advanced Molecular Labs What is L Carnitine and what does it do? VPA Australia New study links L carnitine in red meat to heart disease Harvard Health l Carnitine and heart disease ScienceDirect Intestinal microbiota metabolism of l carnitine, a nutrient in red meat, promotes atherosclerosis Nature Medicine Serum L Carnitine Levels Are Associated With First Stroke in Chinese Adults With Hypertension Stroke