Re: I need info on iodine
The leading cause of either hypoT or hyperT is autoimmunity. TPO and/or Tg antibodies cause Hashimoto's thyroiditis, which leads to eventual total destruction of the thyroid tissue. TSI antibodies overstimulate the gland into making excess hormone, leading to hyperT. Iodine is bad for either one of these, because a damaged gland can't make use of it, making a Hashi's sufferer feel even worse than they already do; and an overstimulated gland doesn't need any extra raw material to make even more excess hormone.
There are relatively few instances where iodine deficiency causes hypoT, I suspect. Bottom line is... Don't supplement with extra iodine unless you've had a blood measurement and have been proven to be deficient.