Potassium Iodide (K1) is a compound that contains Iodine, a nutrient necessary for normal thyroid function. Iodine, in the form of Iodide, is an integral part of thyroid secretions that regulate cellular metabolism and energy production. NOW Potassium plus Iodine also supplies Potassium, a mineral that is essential for the maintenance of healthy water and electrolyte balance, as well as whole body pH.