T3 is the most active form of thyroid hormone but accounts for only 1% of active thyroid hormone. The remainder of the thyroid hormone exists in the form of inactive T4. Thyroxine (T4) has very little effect on the tissue and cells. The body uses two groups from the amino acid tyrosine and four iodine molecules to make T4. The liver and other tissues must remove a key iodine from T4 to make T3. T3 is the primary thyroid hormone that produces energy and speeds up metabolism. Cortisol prohibits the ability of the body to remove the correct iodine to make T3 and thus reverse T3 (an altered T3) is made.

T3 is the most active form of thyroid hormone but accounts for only 1% of active thyroid hormone. The remainder of the thyroid hormone exists in the form of inactive T4. Thyroxine (T4) has very little effect on the tissue and cells. The body uses two groups from the amino acid tyrosine and four iodine molecules to make T4. The liver and other tissues must remove a key iodine from T4 to form T3. T3 is the primary thyroid hormone that produces energy and speeds up metabolism.

Thyroid disorders are frequently missed by healthcare providers when thyroid-stimulating hormone (TSH) and total T3 and T4 levels are used as the sole factors to make a thyroid disorder diagnosis. There are many other factors that cause thyroid hormones not to function well. Stress impairs the thyroid hormone’s ability to function properly.

When the body is unable to make T3 from T4, it produces reverse inactive T3 instead. Cortisol which is produced during times of stress inhibits the body’s ability to make active T3 which results in inactive reverse T3 (an altered T3) being made. Patients can have normal total T3 levels and symptoms of hypothyroidism when most of the T3 consists of inactive reverse T3.

Estrogen also decreases the function of the thyroid hormone. Estrogen increases the production of a protein called thyroid binding globulin. This protein binds the thyroid hormone making it inactive. Thereby, decreasing metabolism and increasing fat deposits. Be sure to ask our staff about having your thyroid hormones checked at your office visit.