Once a key nutrient gets extremely deficient, taking other nutrients which work with that key nutrient cause that key nutrient to get used up and become even more deficient. Using a shotgun approach to hyperthyroidism, in which nutrients are taken at random will most likely make the condition worse. Supplementation has to begin with the key nutrient to prevent it from getting even more deficient. Just about everything makes it worse, causing the person pursuing any of the commonly used nutritional correction strategies extreme frustration. The two main minerals that seem to regulate not only the functioning of the thyroid but also the immune system are copper and zinc.
Zinc acts as the stimulator to the thyroid and immune system and copper as the suppressor.
It appears that when copper becomes deficient, both the thyroid and immune system will run out of control. I believe that the main deficiency in hyperthyroidism is a copper deficiency. I've held this belief for two years since I recovered from hyperthyroidism by supplementing with copper and many other nutrients. I have been studying hyperthyroidism since that time and observing many people with hyperthyroidism improve once they have begun supplementing with copper. There have been no observations in those two years that have caused me to doubt this.