Re: does Synthroid cause fatigue?
Synthroid and other thyroid hormone preparations have few to no side effects on their own. Any "side" effects are almost always related to inappropriate dosing. That said, at the very beginning of hypothyroidism treatment, new hypoT symptoms might appear and/or old ones can become worse. This is most probably what's happening to your daughter. She should hang tight and wait it out until she reaches her optimal dose. Symptoms then should disappear. If symptoms don't disappear, she should assume she's not taking the right amount of Synthroid.