My thyroid went at 6 most post radiation. My TSH went from 5.4 to 50. My T3 and T4 were low in the range so they put me on Synthroid 75/mg. My hands were cold, that was the only symptom. I felt fine, my hair is find and have not gained any weight. I get checked in January to see my new levels since I started it and we'll see if the dose stays the same.