L Carnitine Benefits, Uses, Dosage, Foods, Side Effects Dr. Axe Carnitine: the claims and why it may not work What is L Carnitine? L Carnitine is a naturally occurring amino acid derivative that the human body can synthesize itself. It is mainly found in red meat and dairy products. [1] Core Benefits of Source Naturals Acetyl L Carnitine and Alpha Lipoic Acid Tablets 650mg, 180 ct Smith's Food and Drug Acetyl L Carnitine 500mg Health Thru Nutrition