What is Liothyronine?

What is Liothyronine?
April 16 13:51 2019 Print This Article

Liothyronine is a synthetic alternative of the naturally occurring hormone, triiodothyronine. You will often see both the synthetic and natural version of this hormone referred to as T3. Liothyronine is prescribed in cases involving the thyroid. This gland typically produces T3 naturally, however, in cases where this fails to happen, a synthetic alternative is used.

Thyroid Gland

In the human body, at the base of the neck, is the thyroid gland. It is an endocrine gland that produces hormones that regulate growth and metabolism within the body. The most notable hormones are the aforementioned T3 and thyroxine, also known as T4. The thyroid gland takes iodine, largely from the human diet, to make the two hormones. They are the only compounds made within the body to contain any trace of iodine. T4 is produced in far greater quantities than T3. However, once it has been transported around the body, reaching various cells and organs, it is then converted to T3.

In the cases where the thyroid produces insufficient amounts of the hormones, the body will suffer. This is known as hypothyroidism. There are various causes of hypothyroidism and, while certain diseases and tumours can disrupt hormone production, diet has also been a suspected cause. One of the most difficult aspects of hypothyroidism is that the symptoms, although numerous, are often vague, making them difficult to identify. A person experiencing T4 and T3 deficiency may experience weight gain, depression, extreme sensitivity to cold, and irregular or heavy menstruation. The only accurate method of testing for hypothyroidism is a blood test.

Liothyronine and Levothyroxine

In cases where hypothyroidism has been identified, a synthetic alternative will be prescribed. Alongside liothyronine, there is levothyroxine, which is the synthetic T4. These work to directly increase hormone levels or replace them entirely. After a few weeks, the body will begin to accommodate the replacement hormones and the symptoms will dissipate.

In recent years, however, and within certain countries, T3 has increased in price. As such, it is prescribed less often. Instead, T4 will be offered. This is a logical alternative since T4 is ultimately converted to T3 within the body. Unfortunately, for many people, this conversion process may not happen or the body fails to convert T4 efficiently. Here, no matter what level of T4 is prescribed, the body will continue to struggle with hypothyroidism.


In response to the difficulty of sourcing T3, and since many patients are already accustomed to the positive impact of a T3 prescription, many online pharmacies are seeing a rise in demand for liothyronine. This is because, despite the restrictions and costs that the drug faces within certain countries, online distributors are able to work around the restrictions.

If you believe you may be struggling with hypothyroidism, arrange a consultation with your GP. Once you have confirmed the diagnosis with a blood examination, you can discuss your options. Since many doctors are experiencing the costs of prescription drugs rise, it is not uncommon for them to direct you to a licensed online pharmacy.

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Carol Gilmore
Carol Gilmore

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