Item Catalog Number: LC001149
Thyroxine, otherwise known as T4, is a hormone produced and secreted by the thyroid gland. At the tissue level, T4 is converted into the more active form of the hormone called T3. For this reason, T4 is considered a measurement of total production of thyroid hormone.
High levels of T4 are associated with symptoms such as anxiety, insomnia, diarrhea, and muscle aches and pains. These symptoms collectively are known as hyperthyroidism.
Low levels of T4, known as hypothyroidism, are associated with symptoms such as depression, weight gain, dry skin, hair loss, constipation and cold intolerance.
Fasting is not required. Take all medications as prescribed. Do not take supplements the day of the test. This test is also included in the Life Extension thyroid panel.