I can relate. I saw a personal trainer one time while I was taking lithium and an antipsychotic. She told me that lithium sort of acts like a beta blocker, and I am only going by what she said. She told me I may have to work twice as hard as I otherwise would to acheive the same results. She had trained others on psych meds so I was not her first. Wow I worked soooo hard 7 days a week. 4 days of the week I would go to the gym twice a day plus I do other activities outside of that. I was not trying to loose weight just build muscle. And it took forever to get any results, and my results were not very notible.

Now off meds I have built muscle quite quickly, with much less effort. I am still working on my fitness goals but am much closer now then I ever was when medicated.

So all I really can say from my own experience is yes the meds made it very hard to get results. Not impossible but I am not certain I would have even come close to where I am now despite double or tripple the effort.

Not to sound discouraging, because I was not trying to.loose weight just gain muscle , maybe works a bit different. You have obviously had great success at loosing weight. Which is awesome!!! But it may indeed be harder depending on the medications. I hope you reach your fitness goals, congrats on all the hard work and great accomplishment.