underactive thyroid
"I've been on Synthroid (Levothyroxine) for about a year and a half now. They've changed my dose 4 times so far and I'm currently at 100 mcg.  Once they keep me on a dose for a bit, I feel okay, but with every change I have a few annoying side effects.  I can say that if you take it every day like you're supposed to, it will work eventually. You have to be patient, it won't make you feel great right away. It took me about 3 months.  But it helped with my lethargy, weight and even depression.  It's pretty good if you take as prescribed. If you stop taking it suddenly, the effects of hypothyroidism come back pretty quickly and severely so I recommend taking it as your doctor states."