The bright and the dark sides of L carnitine supplementation: a systematic review Journal of the International Society of Sports Nutrition Springer Nature Link PDF) A Pilot Clinical Trial on L Carnitine Supplementation in Combination with Motivation Training: Effects on Weight Management in Healthy Volunteers l carnitine: Nutrition, pathology, and health benefits ScienceDirect What's L Carnitine and how Does it Benefit your Overall 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.