Underactive Thyroid
"I have been on both sythnoid and levothyroxine
Since march 2015 and have  no issues with  either medicine.  Unless it was my fault for not  taking it. Very bad idea. My levels changed  for the better and my  dr took me off cold  turkey.  Not wise. So I took half a pill to be 25mg and I am fine. Once  in awhile  I feel nervous or anxious so I increase to 50mg . Then go back to 25mg."