Free T3

T3 is a thyroid hormone released in small amounts from the thyroid gland, but is primarily produced by other tissues from T4. This conversion process requires sufficient energy intake (especially carbohydrate), vitamin D, zinc and selenium, and is impaired by stress. T3 is the thyroid hormone primarily responsible for raising the metabolic rate. T3 is often carried in the bloodstream via binding proteins, however some of the T3 is not bound to any protein, making it more readily taken up by tissues. The Free T3 metric is a measurement of the unbound T3. High levels can indicate excessive supplementation, or hyperthyroidism. Low free T3 can also be the result of high estrogen, since estrogen can increase the amount of thyroid binding proteins, leaving less T4 avaible in the blood.

The thyroid hormones govern metabolism, or the body’s energy production. Poor thyroid function be caused by and can contribute to stress. Stress inhibits thyroid hormone production and utilization, and the stress systems tend to take over to compensate for low thyroid function. Thyroid function is vital for maintaining gut health, too. Thyroid hormones govern the growth and proliferation of the cells in the gut, and promote gut motility, support the immune system, and enhance digestive enzyme and stomach acid secretion. Low thyroid function is common in aging and several chronic and age related diseases, as energy metabolism is what fundamentally maintains the structure and function of every cell, tissue and organ system in the body.