Iodine occurs in nature mainly in the sea. On land, the amount of iodine is distributed very unevenly. The best natural food sources of iodine are therefore all products that come from the sea, such as fish, crustaceans and shellfish and seaweed. Iodine Organic comes from organic knotweed that is a naturally rich source of iodine. The product is standardized to contain 150 mcg of iodine per capsule.