ive noticed that when i first started taking Iodine i was wide awake.. my mind was more focused.. my thinking clearer.. my senses more alert.. so i think what happens is that we arent really stimulated... we're just more alert and sensitive...
then after a couple months i went up to 50mg and i noticed after my 2nd week that i was getting sleepy from the iodine..
then i realized the Iodine didnt make me sleepy but very relaxed.. and even though i had energy to stay up til 4am on the laptop for example.. I could say "oh its 4am, I better go to bed" and then once i made that decision i could fall asleep immediately..