Comparison of short term and long term effects of peroral L carnitine intake: clinical implications of elevated TMAO levels in cardiovascular complications L carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment: a randomized, double blind, placebo controlled trial. Semantic Scholar 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 Full article: Effects of high dose L carnitine supplementation on diaphragmatic function in patients with respiratory failure: A randomized clinical trial Altered carnitine acylcarnitine profiles in levothyroxine treated congenital hypothyroid patients with fatigue: An LC MS MS based study from Bangladesh PLOS One