I have been able to lose weight while being treated for hypothyroidism (with levoxyl) but it isn't easy. For me, the only thing that works is counting calories. I was able to drop 20 lbs over about 2.5 months by just increasing my veggies, increasing my protein, watching my carbs and keeping my calories around 1600 a day. Now if I just add some regular exericse to that, I think I will be on track for better success.