L Carnitine Oral Bioavailability NOW l Carnitine Supplement Understanding the Role of Carnitine in TPN and IDPN Therapy Ultra L Carnitine NutriRestore L Carnitine Supplementation in Patients with Advanced Cancer and Carnitine Deficiency: A Double Blind, Placebo Controlled Study ScienceDirect If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy. Why is L carnitine used for Medium Chain Acyl CoA Dehydrogenase (MCAD) deficiency?