if you want iodine you can try iodoral my mom used that and had good results.
Also cayenne pepper is supposed to be good for thyroid as well as Rhodiola aka"golden root" or guggullipid extract
Brown, R., et al. Rhodiola rosea: A phytomedicinal overview. HerbalGram. 56:40-52, 2002.
English, J. New research on thermogenesis. Vitamin Research News. April 2000.
zinc, selenium, tyrosine are supposed to be good as well.
Avoid fluoride from toothpaste and tap water for sure.