Total Triiodothyronine (T3)
Frequently Asked Questions
The thyroid hormone triiodothyronine (T3) is measured, and the phrase “T3 count” is commonly used to describe this metric. T3, or triiodothyronine, is an important hormone that controls energy levels and metabolism.
Several medical issues can result in a low T3 count, including:
● Low T3 levels are most often brought on by hypothyroidism. Insufficient production of thyroid hormones by the thyroid gland causes hypothyroidism.
● Thyroid dysfunction: Low T3 levels have been linked to thyroid diseases such Hashimoto’s thyroiditis and postpartum thyroiditis.
● Certain medicines, including antithyroid drugs, lithium, and amiodarone, have been shown to interfere with thyroid function and reduce T3 levels in the body.
● Decreased T3 production can also be the outcome of medical interventions like radioactive iodine therapy or surgical excision of the thyroid gland.
● T3 levels drop when the body’s metabolism is disrupted, as it happens during starvation, extreme calorie restriction, or serious sickness.
Multiple causes can contribute to an abnormally high T3 level.
● When the thyroid gland generates too much of the hormone thyroid, a condition known as hyperthyroidism results.
● Thyroiditis: Thyroid inflammation, whether from autoimmunity or infection, can temporarily raise T3 levels by releasing hormones from storage into the circulation.
● High T3 levels can be caused by thyroid growths such nodules or tumors that generate too much of the thyroid hormone.
● A number of drugs, including amiodarone, have been linked to increased T3 levels in patients.
● T3 levels may rise during pregnancy because of an increase in thyroid hormone synthesis.
The T3 level represents the hormone’s concentration in the blood. As part of a battery of thyroid function tests used to evaluate thyroid health and identify a range of thyroid diseases, it is routinely evaluated. Conditions affecting the thyroid include hyperthyroidism (excessive production of thyroid hormone) and hypothyroidism (insufficient production of thyroid hormone), among others.
Given the complexity of thyroid function and the interplay of various hormones, a T3 value alone may not paint a whole picture of health. Therefore, in order to gain a complete picture of thyroid function, doctors will commonly check T3 levels alongside thyroxine (T4) and thyroid-stimulating hormone (TSH).