Hypothyroidism and Thyroid Hormones

More details on the T3 Thyroid Hormone

T3 is called triiodothyronine when it is produced naturally within the body.

In synthetic form for medication T3 may be referred to as: liothyronine sodium, liothyronine or synthetic T3.

Common brand names of T3 medication are:

  • Tertroxin
  • Cytomel
  • Cynomel

The most important things to know about T3 are:


Hypothyroidism occurs when the body does not have sufficient effect of the biologically active T3 within the tissues of the body. 

It can happen through low levels of thyroid hormones, poor conversion from T4 to T3, low levels of other co-factors like cortisol or ferritin etc., and many other more complicated processes that are not working well any more.

Some of the main symptoms associated with hypothyroidism include:

Hypothyroidism Diagnosis and Thyroid Blood Tests

Primary hypothyroidism is usually detected when numerous symptoms begin to appear, which prompt the patient to seek medical advice.

As the thyroid gland is no longer able to adequately respond to the demand of TSH, this usually results in lower than normal levels of T4 and T3 appearing in thyroid blood test results.

In addition, TSH levels are often higher than normal. This is because the pituitary gland is attempting to stimulate more thyroid hormone production by releasing more TSH.

More details on the T4 Thyroid Hormone

T4 is also known as thyroxine when it is produced by the thyroid gland.

Its proper chemical name is 3,5,3',5' tetraiodothyronine but as you can see it is easier to call it T4 (due to its four iodine atoms).

In its synthetic medication form T4 is often referred to as: Levothyroxine, L-Thyroxine or Synthetic T4. However, there are many brand names for T4 medication and sometimes it is just referred to by the brand.

Examples of T4 medication brands are:

Subscribe to Hypothyroidism and Thyroid Hormones