is no different than eating idoine rich food. Lack of proper nutrient intake leads to deficiency, taking lugos fulfils the bodies nutrient needs. Stop taking it and if your not getting enough Iodine
from food then your body once again goes into a deficient state and reverts to suboptimal function.
Iodine isnt a drug, its an essential nutrient and like every other nutrient, short your body of it for too long you will suffer.
12% is pretty strong, probably too strong for topical application but should be fine for oral consumption.