After my initial detox symptoms which lasted about 6 weeks, I am showing no symptoms for last 4 months. I have played around with dosage ranging from 12 mg to 150 mg a day. I haven't been tested for TSH levels, but haven't maintained high dosage of Iodine supp for extended periods either. The medical literature on the Iodine4health website shows that the increase in TSH levels is temporary when it occurs and after several months it goes back down. Is that just the body readjusting? Dunno.