Managing your subclinical hypothyroidism

Information sheet for patients

Is this information for you?

This information is for you if:

  • you have had a blood test and were told that you have a slightly underactive thyroid
  • there has been a change in your health and you are worried it might be related to your thyroid.

Measuring your thyroid function

A blood test can measure two hormones to show how well your thyroid is working.
Subclinical hypothyroidism is when the level of only one of these hormones, the thyroid stimulating hormone (TSH), is abnormal.

What affects TSH levels?

Many things can change your TSH level, including illness, medicines, supplements, age and gender.1,2

Symptoms of the thyroid not working properly (thyroid dysfunction)

Although thyroid dysfunction can cause weight gain and fatigue, these symptoms can also be caused by other factors. Many people find that changing their lifestyle (for example, eating differently and getting more sleep) can help to reduce these symptoms.

Thyroid tests

  • Thyroid tests are not recommended for people who are completely well.
  • Your general practitioner (GP) will recommend testing for thyroid dysfunction only if you have specific symptoms.
  • If you have any concerns or questions about thyroid tests, please speak with your GP.
  • In most cases, subclinical hypothyroidism can be monitored by your GP and does not need to be treated with medicines. 
  • You will not need any treatment (including medicine or supplements) unless you and your GP think that your abnormal hormone level is causing health problems. Your GP will advise the most appropriate treatment for you.
  • You will not need an ultrasound scan unless there is a lump in your neck. If there is a lump in your neck, see your GP as soon as possible. They can examine your neck and decide if you need an ultrasound or any other tests.

Treating subclinical hypothyroidism may not help your symptoms, and instead may cause more harm than good. For example, unnecessary thyroid treatment is linked to increased risk of strokes, osteoporosis and bone fractures.3–5

What about other tests, such as T3?

There are some other thyroid tests (including one called triiodothyronine or T3), but these tests are for patients who have an overactive thyroid, not an underactive thyroid.

You may have symptoms such as lethargy, tiredness, low mood, a change in appetite and weight gain. However, your thyroid is not usually the cause of these symptoms, even if your test results show that you have slightly abnormal TSH levels.

Changing some aspects of your lifestyle (like those listed below) can reduce, or eliminate, the symptoms:

  • physical activity – aim for 30 minutes of moderate-intensity exercise on most days
  • good nutrition – eat a range of foods, including plenty of vegetables and some fruit
  • sleep – plan your sleep times and make sure you have enough sleep so you wake up refreshed
  • mental health – manage your stress and discuss mental health concerns
  • alcohol and drugs – reduce your consumption of alcohol and other drugs.

Talk to your GP and allied health practitioners (for example, dietitian), who can help you develop a plan for making appropriate changes to your lifestyle. If your symptoms get worse, please see your GP.

  • If you have had a thyroid test and are considering another one, it is best is wait a few months.
  • There are other tests (such as antibody tests) that can help to predict if your thyroid is going to become worse over time.
  • Talk to your GP about your overall health. Advise them if you are taking any supplements or feeling unwell, as these things can impact your TSH levels.