The supplement secret for hyperthyroidism? When dealing with hyperthyroidism or Graves' disease, L carnitine can be a total game changer. It helps block the entry of thyroid hormone into the cell nuclei, potentially L Carnitine Benefits, Sources, and Side Effects 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. Frontiers Association between fatigue, peripheral serotonin, and L carnitine in hypothyroidism and in chronic fatigue syndrome