What Does Liothyronine Do and Who Should Take It?


Liothyronine (leo-thigh-ro-neen) is a synthetic version of the thyroid hormone, T3, which is usually produced in the body from naturally occurring T4 thyroid hormone – when the patient’s thyroid is functioning properly that is. If the patient’s body is unable to convert T4 into T3 or cannot do it in sufficient quantities, a doctor might prescribe a dose of liothyronine to balance the thyroid hormones. 

What is T3 and T4? 

These two labels refer to thyroid hormones: T4 is produced naturally in the body, and from this, T3 is created, again, within the body. People who have had thyroid damage or surgical removal of the thyroid will have to take a mix of the two hormones, but those who produce sufficient quantities of T4 (the synthetic equivalent being called levothyroxine), will only have to take T3 or liothyronine. 

What Conditions is Liothyronine Prescribed For? 

The main conditions for which liothyronine is prescribed are thyroid cancer and hypothyroidism, and it can also be beneficial for patients suffering from myxedema coma, a rare and serious condition that usually involves severe thyroid issues alongside other challenging conditions. It is also used in conjunction with levothyroxine to treat hypothyroidism that involves both T4 and T3 production. 

What Form Does Liothyronine take? 

The most usual form for liothyronine is as a tablet, usually to be taken at the same time every day to ensure that hormone levels remain as steady as possible. However, liothyronine can also be administered in the form of an injection, especially in serious medical crises. Liothyronine gets to work much more quickly than levothyroxine, which can be vital in a life-threatening situation.

sad aged woman

Can Anyone Take Liothyronine? 

Liothyronine is a prescription only medication so you should only take it if you are under medical supervision for a diagnosed condition. Because one of the side effects is that of weight loss, some people try to access the medication to use it to treat their obesity. However this is very much contra-indicated for people who have fully functioning thyroids – the weight loss experienced by liothyronine patients is usually a correction of their metabolic dysfunction – a dysfunction caused by their underperforming thyroid! 

Some Side Effects and Warnings 

Liothyronine is a very strong medication, being some three or four times 

stronger than levothyroxine. You should always only take the recommended dose and it is strongly advised that you take your medication at the same time or times each day to maintain good levels of thyroid hormone in your body, without running low. The list of side effects is very long too, including, amongst other things:

  • Digestive issues 
  • Anxiety 
  • Vomiting 
  • Menstrual changes 
  • Insomnia 
  • Greater sensitivity to heat/ sweating 

While you should be aware of these side effects (and the others – read the insert in your medicine pack for details) and alert your doctor to any unwanted reactions, especially while treatment is new and you and your doctor are working to find the appropriate dose for your age, weight and body size, rest assured that soon enough, you will begin to feel the benefits as liothyronine allows you to get on with living your best life.