Iodine SynergyIodine Synergy contains potassium iodide to support normal thyroid function, including balanced thyroid hormone production and healthy breast and prostate tissues. Potassium iodide is a weak salt and separates easily in the intestine, leaving free iodide ions to join iodine I2. The selenium in this product works synergistically with iodine to support the normal conversion of T4 to T3 and provides antioxidant protection to the thyroid gland.