Iodine lowers thyroid hormone levels and can kill fungi, bacteria, and other microbes like amoebas. Iodine is used in medicine to treat hypothyroidism and hyperthyroidism. It can also be used as an antiseizure drug during pregnancy because it has no significant side effects on the baby. Iodine is found in natural sources such as saltwater, seaweed, dairy products, and meat. It is also produced chemically from potassium iodide. The recommended daily allowance (RDA) of iodine for adults is 150-200 mcg/day. Higher doses are used by some bodybuilders to help build muscle mass. Iodine is needed for healthy immune function and preventing infections. It plays a role in the production of hormones such as thyroxin and triiodothyronine. Iodine is also required for proper brain development during fetal life and infancy. When you have low iodine intake, your body will use more of its store of iodine to make more thyroid hormone. This causes the thyroid gland to grow bigger. As we get older, our need for iodine decreases, so there is no need for a large-scale increase.