Welcome!
I have an overactive thyroid myself, and I'm on methimizole to calm it down.
I've been fasting 2 days a week since January 8, and I have to say my weight loss has been slow - 3.5 pounds total. But this is to be expected with my thyroid medication, so I'm not terribly concerned.
My hope is that with fasting fixing all of these other issues, maybe it will have a beneficial effect on my thyroid as well? I haven't found *any* information at all about the effects of this on the thyroid though. This is only my hope. I will be going for another blood test in four weeks, and we'll see what happens.
Perhaps we should be asking this question of the experts in the Nerd forum

Welcome aboard!