Active Active Thyroid Levothyroxine :what Exactly Is It For-over Or Under Active Thyroid?

Levothyroxine :what exactly is it for-over or under active thyroid? - active active thyroid

I `m all about the difference in drugs used for more goods and thyroid confused.
Someone told me that you are really the same medication (levothyroxine) for both diseases.
is that true?