Hi,
I had my thyroid removed in July and RAI in August. When advised that no maore RAI required at this stage. I started on 150mg thyroxine but haven't been feeling too good I waited the six weeks to see if things improved. I have just had my dose lowered to 125mg. I think it really depends on the individual and how your body adjusts to the medication.
It kind of depends. If you get lucky and your initial dose is correct for you, you should feel better in about 6 weeks. A lot of time, though, it takes some tweaking of your dose to find what's right for your body. For example, the doctor may start you out on 150mcg of Synthroid, but when you get your next blood work done, your TSH may be too high or too low, then your doctor will adjust your dose either higher of lower and do more blood work in 6 weeks. Hopefully, you have a good relationship with your doctor and he/she will look at your symptoms in addition to your lab values.
Good luck to you!
Amy
Papillary Thyroid Cancer
First diagnosed 1985
Recurrence 2008