Although we all need Iodine and many of us do not get enough of it, if you have any reason to suspect that your thyroid us under functioning please get some blood work done and test for both elevated TSH (over 3) and TPO antibodies to ascertain whether it is autoimmune driven, or not. About 80% of all hypothyroid/under functioning thyroid cases are Hashimoto's--it is the most common form of hypothyroid issue. If you are autoimmune then under no circumstances should you use Iodine supplementation. It will worsen your condition.
Not to freak you out....just offering a little wise precaution.