Levothyroxine -- the generic version of Synthroid. Or Levoxyl, which is a brand name for the same thing. I used to be on that for a number of years, but some people do not respond to the generic version, for whatever reason, which was the case with me, so they made me switch back to Synthroid. (Which sucked, because it's like six times more expensive!) Thyroid stuff is tricky. The medication is so tightly titrated that a little difference can have a huge effect. It's probably worth asking your MD to check your TSH level if he/she is going to do blood work anyway. I was thrown because your previous post said your thyroid was "hyperactive," which isn't the case with hypothyroidism. Your thyroid is actually under-performing, that's why the TSH level is too high, it isn't uptaking the hormone as it's supposed to in order to regulate your metabolism properly. Sorry you're having to deal with that on top of having sexual issues -- like I said, I've been managing thyroid issues since childhood, and sometimes it's just really frustrating. You go along for quite a while and everything seems okay, and then you just go wonky and they can't figure out why. Plus it can be difficult to try and make yourself understood to a physician who isn't an endo specialist -- it isn't until I started seeing one that I could make anyone understand that I know when I feel best and what range I'd like my TSH in.