For me it's the same effect. A small drop of tincture of iodine has the same 'resetting' effect as 100 mcg of T2 (3-5 diiodothyronine). Taking both has no different effect, either for magnitude or duration, nor does taking more of either.
Supplemental T2 does act on the thyroid gland to reduce T4 production, so if you have thyroid dysfunction, it's possible that you might have a negative effect. I didn't notice any such effects.
I did discover that the T2 capsules did deteriorate after several years (the bottle wasn't sized for being taken once every 21 days). I was horrified that maybe T2 had stopped working for me, but iodine worked, so I looked at the date on the T2 bottle. May 2014
