Yes I've been on thyroid medication for underactive thyroid for about 15 years. I don't know what kind of effect intermittent fasting will have -- so I continue to take it even while fasting. I also take a multivitamin, supplemental magnesium, calcium and potassium, grape seed extract, and sometimes a melatonin at night.
I waver back and forth with the soy -- depending upon which study I've recently read I guess. I just watched a documentary on the Okinawan's and longevity -- hence the current pro-soy stance. (LOL)