I have an underactive thyroid. So I'm on synthroid. I've really not noticed that the medication has helped me actually lose the weight but without it I don't have the energy to get out of bed. My Doc will, occ, put someone on a very low dose to see if it helps, if their numbers are close enough to do it. It's dangerous to be on a thyroid medication without any indications at all that you need it . Too much can cause rapid heart rates. We have had women come in our office that were put on the med by another Dr for weight loss. Only to find they've developed an irregular heart rate.
So anyone wondering about thyroid replacement without indication, or borderline testing, it really won't do anything for weight loss.
I just wanted to post the dangers because we've seen a couple ladies recently who were put at risk by other Dr's who felt it would help them with weight loss.

Just an fyi.