It is likely that I have resistance to thyroid hormone. I am now on 135 mcg T3 as a divided dose and feel no difference at all compared to how I felt taking nothing. I have also been diagnosed with a mitochondrial defect which I feel is secondary to the thyroid hormone resistance. I am wondering if anyone has thoughts on this correlation and if supplementing with high dose B vitamins, especially B1 could be helpful. My thinking is this....if transport of thyroid hormone into the cell is an energy dependent process requiring ATP then would supplementing with B1 and/or other B vitamins needed for energy production help to overcome this resistance? Just a theory... makes sense to me but I cant find any research on this other than a study with Hashi and B1 that seemed to improve fatigue.