Underactive thyroid

Most people have heard about the thyroid gland; a very important gland that lies inside the front of your neck. In many people this gland can be underactive and this can result in a whole host of problems for that individual. An underactive gland simply means that the thyroid is not making enough hormones and as a result you will get a variety of symptoms such as feeling depressed and tired. There are tablets that you can take in order to replace the hormones that your body is not making enough of and this works quite well. However finding the right balance of hormone replacement can be difficult and involve a bit of dose adjusting. There is a medical term for an underactive thyroid known as hypothyroidism, this is important to know as you may hear this term being thrown around when the doctors are talking about you. This article discuses what it means to have an underactive thyroid and looks at the latest research and evidence to give you the information to seek treatment.

What is it?

As mentioned earlier the thyroid is a small gland on the front of your neck that is incredibly important in balancing most of your body’s processes. The thyroid gland is responsible for making hormones that send messages around your body in your blood stream and control important processes such as metabolism. The hormone that is most important and is made by your thyroid is thyroxine. Now this is a hormone that is responsible for controlling how fast your body uses the energy that it gets from food. Most commonly the reason that your thyroid becomes underactive is because your own immune system has attacked it. Unfortunately it is not fully understood why this happens, however it is thought that genetic material you inherit from your parents may play a part. Reasons for thinking this are that you are more likely to suffer from hypothyroidism if one of your siblings has it. This immune attack is not the only reason that you get an underactive thyroid and in fact some of the less common causes include radiotherapy, surgery, another medical problem, or other medications. In some cases women who have just given birth can develop an underactive thyroid.


In most cases the symptoms of an underactive thyroid can be quite mild and rather vague. However it is important that you know what they are as this is a very important condition to recognize. Symptoms associated with this condition may be caused by something else and so it is hard to make a diagnosis, however there are blood tests that can be done to see if the thyroid is underactive. Some of the symptoms that you may get if you have an underactive thyroid include: thinking more slowly or having difficulty concentrating, feeling tired, feeling down, putting on weight for no apparent reason, having dry skin, having constipation, feeling the cold more than other people and having irregular periods if you are a female. Symptoms can become worse over time if your condition is not treated and after months or even years of no treatment you may notice: that you feel depressed, that you have dry and flaky skin, have coarse hair, feel really depressed, have a hoarse voice, feel weak and have real difficulty concentrating and put on weight no matter what you do to try and lose it. In some very rare cases those who are not treated for an underactive thyroid can go into a coma.


An underactive thyroid is best treated with hormone replacement tablets containing thyroxine. There is a name for this form of replacement thyroxine that we call levothyroxine. Most people will need to be treated for the rest of their lives, however you may not need treatment until you develop symptoms. If you do get symptoms then these replacement tablets will certainly make you feel better. These tablets are usually taken at a dose of one per day on an empty stomach before breakfast. There will most likely be quite a bit of experimentation at the beginning of treatment as your doctor tries to figure out what dose is best for you and you will need to have regular blood tests to check your levels. Most of your symptoms if not all of them should improve, however this medication will often take several weeks to work and so do not expect a magical cure overnight. Women who are taking this medication after the menopause should be extra careful as it may make their bones more fragile. Your doctor will most likely give you the lowest dose possible in order to prevent this from happening. If you are given a very high dose of this medicine then it is possible for you to develop an irregular heart beat known as atrial fibrillation and so your doctor will be cautious about giving you too much.

Some people will have an underactive thyroid but will not get symptoms and if this is the case you will need to discuss with your doctor whether you should have treatment or not. It is possible that medication may prevent you from getting symptoms in the future or make your heart better but this research is not very convincing. There is also a small chance that the levothyroxine medication may make you more anxious than you would have otherwise been.


If you are not treated and you have symptoms of an underactive thyroid then there is a good chance that your symptoms will worsen. This is not such an easy statement to make if you do not get symptoms but have been told by your doctor that you have an underactive thyroid. There is some research that says you may be at increased risk of heart disease if you have an underactive thyroid and are not getting treated, however this research is not very good and that point is not known at this point.

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The content on this page is for informational and educational purposes only and does not constitute professional medical advice. Patients should not use the information presented on this page for diagnosing a health-related issue or disease. Before taking any medication or supplements, patients should always consult a physician or qualified healthcare professional for medical advice or information about whether a drug is safe, appropriate or effective.