Frontiers Association between fatigue, peripheral serotonin, and L carnitine in hypothyroidism and in chronic fatigue syndrome 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 Adding L Carnitine and Selenium to Methimazole in Graves' Disease: A Prospective Randomized Trial on Thyroid Markers and Quality of Life ThyroSoothe