the thyroid makes its hormones with any halide available. you free up the bad halides, they dont work at the other end. thats how i understand it. i was diagnosed with cold body syndrome(wilson's thyroid syndrome). the KI shut my already inadequate metabolism off like flipping a light switch. ouch! this is seen by allopaths as a function of the Iodine in excess. i cant tell you how much more we know than they do.