Eltroxin 125 Tablet is a synthetic thyroid hormone that works by replacing the thyroid hormone in the body when the natural production of thyroid hormones is not sufficient to meet the needs of the body. Eltroxin 125 Tablet is primarily taken for treatment of hypothyroidism or low secretion of thyroid hormone. It comprises thyroxine which is a synthetic thyroid hormone that is chemically similar to thyroxine produced by our thyroid gland. Thyroxine helps to replace missing thyroid hormone and/or to relieve stress on the thyroid gland.