L Carnitine is not a magic fat burner It won't melt fat, build muscle, or replace hard work. The only thing it burns is your money Stick to the basics Intermittent Fasting 101 TrueFit Nutrition L Carnitine: A Fat Loss Myth or Supplement Staple? How L Carnitine Supports Weight Loss During Intermittent Fasting 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.