Is there not a risk of actually shutting the thyroid off? I believe that occurs if one takes more than the recommended dose.
I was not talking about KI. I mentioned liquid iodine, like Atomadine, a much less intense but still helpful protection. You do a skin test first, then a patch of the liquid over the iodine. Not a permanent nor sustained treatment.
Also very good if flying over the north pole or on a long trans-atlantic or trans-pacific flight as exposure to sun radiation is higher when in flight.