Understanding the Benefits and Uses of Carnitine in Health and Fitness Fitness Health Is L Carnitine safe for athletes at doses up to 6000 mg day? Consensus Is L Carnitine Safe? Watch FIRST BEFORE Taking L Carnitine Supplements Top 7 L Carnitine L Tartrate Uses for Fat Loss 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.