the body needs both Iodine and iodide. most people here have used Lugols in order to provide both in one supplement. i am convinced that Lugols is too high in percentage of I2 in order to get the benefit of the KI in it. IOW, with Lugols you can get all the I2 you need but may be cutting the KI short. and if one wanted more KI to deal with an infection or something, lugols is limiting due to the high I2(or low KI, depending on your POV.)
iodine is THE mineral that convinced me to supplement beyond diet.