The IOSAT Potassium Iodide Tablet works by saturating the thyroid with stable iodine so it will not absorb radioactive iodine released in the event of a nuclear accident. This 14-day supply is designed to protect an adult from the serious effects of radioactive iodine, which has a half-life of eight days. The IOSAT Potassium Iodide Tablets includes 14 130-mg tablets.