The Benefits of Amino Acids for Hashimoto's Dr. Izabella Wentz, PharmD L Carnitine is Underrated. New Meta Review Reminds Us Why. There are 3 main types of thyroid medications available T4 T3 (usually combined with T4) NDT desiccated thyroid (a combination of T4 + T3) Most are widely available Successive thyroid storms treated with L carnitine and low doses of Methimazole The American Journal of Medicine Surprising Interactions with Levothyroxine (Synthroid) and Herbal Supplements