Im not sure if this has been proven, but here is my thought on this (backed up by some anecdotal plus some other info scattered around). Since the thyroid/adrenals and testosterone are so interrelated, I believe that by using (especially t3) thyroid meds, you can (1) clean out reverse t3 and thus reboot the thyroid. Also you can (2) rebalance your thyroid, allowing your cortisol and adrenal levels to rebalance, which then will rebalance an underactive thyroid (especially when tsh is normalish but free t3 and free t4) are off. So those are just two ways I think you could theoretically 'fix' your thyroid. Another thing is to look into adequate iodine levels and reduction of goitergenic foods and fluorine/bromine.