Understanding the Benefits and Uses of Carnitine in Health and Fitness Fitness Health 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. The Role of l Carnitine in Mitochondria, Prevention of Metabolic Inflexibility and Disease Initiation L Carnitine: Benefits, Uses, and Side Effects Lifespan Research Institute