Levothyroxine is a medicine that helps people who have problems with their thyroid gland. The thyroid gland is like a little butterfly in your neck that makes a special hormone that helps your body work properly. Sometimes, people’s thyroid gland doesn’t make enough of this hormone, and they feel tired and have trouble growing like they should. Levothyroxine is a medicine that can give their body more of this special hormone, so they can feel better and grow like they’re supposed to.