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. Association between fatigue, peripheral serotonin, and L carnitine in hypothyroidism and in chronic fatigue syndrome American ME and CFS Society Frontiers Thyroid hormones and carnitine in the second trimester negatively affect neonate birth weight: A prospective cohort study Direct effects of thyroid hormones on hepatic lipid metabolism Nature Reviews Endocrinology L carnitine reduces hyperthyroidism symptoms