A nuclear war isn’t the only nuclear disaster you should prepare for. Trucks or trains hauling spent fuel rods can create a nuclear crisis anywhere just as quickly. In the case of an emergency radiation leak in your area, you take 1 tablet a day for 14 days. IOSAT tablets 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 effect of radioactive iodine, which has a half-life of eight days. Includes 14 130-mg tablets. These tablets have a shelf life of 5-6 years, and each package is date stamped with an expiration date, aiding you in knowing when to replace them.