If you are worried about thyroid peroxidase, then make sure you take 200 mcg selenium 2x per day, Vitamin C 1,500 mg 2x per day and possibly tyrosine 500 mg 2x per day. Magnesium is helpful as well. This what Dr Tenpenny suggests to do for a couple of months before starting iodine at a very low dose if you have Antithyroid antibodies.