Healthy Thyroid Gland Function

Thyroid Stimulating Hormone (TSH), Thyroxine (T4) and Triiodothyronine (T3)

The pituitary gland, located within the brain regulates thyroid gland activity by secreting a hormone called Thyroid Stimulating Hormone (TSH). TSH travels to the thyroid gland to signal the production of the two main thyroid hormones – Thyroxine (T4) and Triiodothyronine (T3).

Thyroid hormones are like a throttle, boosting your body’s metabolic activity. When the thyroid gland is under active the internal metabolic furnace is turned down. T3 is the most active thyroid hormone.

Triiodothyronine (T3)

T3 is converted from T4 with low levels of T3 indicating that conversion is not taking place.

Stress is the major reason for this as cortisol blocks conversion. Other factors include nutrient deficiencies, autoimmune disorders, hormone imbalances, toxicity or infections.

If T4 is not converting to T3 it may instead convert to reverse T3. This condition is known as ‘reverse T3 dominance’. If reverse T3 levels are raised metabolism slows down, causing symptoms of hypothyroidism.