very easy
buy a real bottle and it will have skull bone and say
"poison"
otherwise i have a book that listed in in 1950 as one of the top medical poisons with the side effect of causing sterility and birth defects....
beyond that, search all you desire and if you ever read anything that says lugol's is not a poison, then i hope you have common enough sense to know that author is a liar.....the iodine forum is maxed out with such irresponsibly info that has helped many people not only be ripped off, but poisoned as well..
if you have taken lugol's into your body, then yes, it can be proven by doing a data labs tissue test that will show your iodine locked up in your cells.