FDA says 130mg of Potassium Iodide a day can save your thyroid from thyroid cancer in a nuclear emergency. In the past Fukishima disaster, there was a run on potassium iodide worldwide and it became unavailable. Don't wait for a disaster to hit where you live to try to order it. Don't take unless directed to by health officials during a nuclear emergency. Recommended to only take during the few days you are exposed. Don't exceed taking 10 days.