thanks for clarifying - you doctor may have been giving you a misleading impression - he is prescribing to get your TSH in range, and hoping this will also lead you to lose weight. It may do, it may not, i don't know. in my case, i was not over normal BMI, but had gained a little weight, but more especially inches round the middle, and getting to a perfect thyroid profile with medication did not change that at all - or for my relatives. Keeping weight from going up became routine for all of us. But everyone is different - your doctor is likely to know more about what might be likely in you case.