In 2011 my tsh suddenly jumped to 3.11 (had previously been in the 0.75 - 1.50 range), at which time my doc switched me from 75mcg synthroid to 50mcg of levothyroxine. Now in 2015 my tsh has dropped to 0.68 (0.35 is the bottom end of our medical plan's range), and my doc says to stay on same dose of levothyroxine (no t3 or t4 was run in either testing as far as I can tell when I look online). This doesn't seem right to me. In the last 6 months I have noticed more brittle nails and hair loss, as well as sluggishness. However I have been successful in losing 40 lbs in the last 6 mos on purpose. Any thoughts? Thanks!!