takes time, and for some of us, doesn't happen like it's supposed to. Cytomel
is a T3 only med, about 4 times more powerful than T4 meds, is fast acting and short lived, so will get into your system quickly. Most likely, your doctor is trying to prevent your going hypo by using the cytomel.
I do hope that he doesn't give you a real high dose AND that he does frequent testing to make sure your levels don't go too high.