I wanted to add that I too take T3 and T4. I have my thyroid medication bioidentically made. However, you can get a prescription for both. Some docs wont give the T3 and if you need it (specialized blood test is needed) and do not receive the prescription, then it will be profoundly hard to lose weight.
AFter getting my thyroid corrected, I was better, but it was still kinda hard to lose weight. I certainly had more energy to exercise, etc.
Then, I cut out carbs (with the exception of lots of vegetables) and the weight loss (FINALLY) started to happen.
If you are unsure if your thyroid medication is where it should be, consider getting a second opinion.
And honestly, I do believe low or reduced carb is the way to go for those over 40 with hypothyroidism.