The thyroid hormones thyroxine and triiodothyronine contain iodine. The thyroid gland naturally uses iodine to produce thyroxine and other hormones. Iodine is needed in trace amounts for the production of thyroid hormones such as thyroxine. Treatment consists of a daily dose of thyroid hormone (thyroxine) by mouth. Hypothyroidism is a disease diagnosed by decreased levels of serum thyroxine (T). Hypothyroidism is managed with replacement of the hormone thyroxine. Total thyroxine (Total T) is generally elevated in hyperthyroidism and decreased in hypothyroidism. For hypothyroid patients on thyroxine, measurement of TSH alone is generally considered sufficient. TTH stimulates the release of thyroxine and triiodothyronine from the thyroid. Iodine is an essential component of thyroxine. High estrogen and thyroxine levels cause it to increase. Amiodarone is structurally similar to thyroxine and also contains iodine. Treatment consists of lifelong administration of thyroxine (T4). They contain a mixture of thyroxine (T4) and triiodothyronine (T3). This is one of the essential steps in the formation of thyroxine (T4).