L carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment: a randomized, double blind, placebo controlled trial. Semantic Scholar Adding L Carnitine and Selenium to Methimazole in Graves' Disease: A Prospective Randomized Trial on Thyroid Markers and Quality of Life Graves' Disease and the Manifestations of Thyrotoxicosis Endotext NCBI Bookshelf 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