Most of us here, aren't very open minded when it comes to diet pills. How about if I pretend to "be your doctor" and just say "no"?.. LOL Those pills really can have an adverse reaction since you're taking beta blockers (I used to be on them, too).
Diet pills usually don't work, especially for those of us with hypothyroidism. The key, there, is getting our doctors to prescribe an adequate dose of thyroid medication to bring thyroid hormone levels up high enough to get metabolism back to a normal state....
You might want to take a quick look at the thyroid forum for more information. I'm guessing you might have Hashimoto's, which often starts with hyperthyroidism and alternates back and forth before ultimately transitioning to hypothyroidism.
Typically, diet pills don't work, but the problem is, that they aren't meant for long term use, so if, by chance, they do work, when you go off them, you'll gain back whatever you might have lost, often even more.
Opt for reduced calories, with about 1/3 of them protein, plenty of veggies, and lots of exercise...
I've done reduced calories, I work a highly physical job 4 days a week 8 hours a day. I spend my free time walking and playing with my dogs. It stopped working months ago, even when I was in the hyperthyroidism stage. I'm out of options. I guess I'll just be stuck this way forever.
I didn't mean for you to give up. I've been struggling with hypothyroidism for years and along with that, I've struggled with my weight, when I never weighed more than 120 lbs in my life, before that and that when I was pregnant. You can imagine what if felt like to gain 30 lbs in < 3 months and not be able to get it off, no matter what I did. At the time, I, too had a physically demanding job that I worked 8 hrs/day, 5 days/week, then on weekends, I did yard work, house work, cared for an elderly aunt, etc. Yet my doctor had the audacity to tell me I needed to "eat less, move more".
The problem so many of us (myself included) have is that our doctors are not willing to give therapeutic doses of thyroid hormones to bring our metabolism up to what it should be. You sound like you might already have flipped over to hypo. I'm not sure what tests your doctors is doing routinely, but many of them only test TSH, which is not the best diagnostic. Actual thyroid hormone levels can be too low before TSH levels become too high, or some doctors won't treat until TSH levels hit higher levels.
What I found with lower calories is to make sure I have protein with every meal/snack. Protein fills you up more quickly and keeps you feeling fuller longer. My doctor wanted me to really load up on protein, but what I'm reading is to limit protein to about 30% of your daily calories. You can fill up on veggies - most are considered "free", because they have so few calories - just limit things like corn, green peas, lima beans, etc.
You might also want to look into insulin resistance. That's another issue I deal with. Insulin is often called the "fat storage hormone" and it will shuttle any sugar or simple carbs right into the fat cells to be stored as fat. Do a search for low glycemic diet and center your meals around the foods that don't increase your blood sugar levels. That means eliminating sugar, nearly all processed foods, white flour, including breads, pasta, etc. Opt for whole grain breads and pasta, brown rice, etc. Those don't spike your blood sugar like the white, processed versions, which in turn won't spike insulin levels.
While we're all looking for that one thing that's going to help us lose the weight, it's just not there. I keep reading about all the things that speed up metabolism, burn more fat, curb the appetite, etc and believe me, I think I've tried most of them in one form or another. My medicine cabinet resembles the weight loss aisle at your local health food or discount store... I have a cabinet full of various protein shakes, etc. If there was a magic bullet out there, I'd have found it by now!! But the truth is, most of that stuff doesn't work... we can only take so many pills and drink protein shakes for so long, then we have to eat.