How Should I Use Thyroid Supplements? 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. Adding L Carnitine and Selenium to Methimazole in Graves' Disease: A Prospective Randomized Trial on Thyroid Markers and Quality of Life Thorne Research L Carnitine L Carnitine Supplement The Natural Athletes Clinic