How does thyroid stimulating hormone affect your health?
Thyroid-stimulating hormones play a key role in controlling the release of multiple hormones in your body that are important for the normal functioning of many of your body’s normal processes. When your TSH levels are out of balance, it can disrupt how your body functions and cause a range of symptoms from unexplained weight loss and irregular menstrual periods (in women) to depression and unexplained fatigue.
In this article, we explain how thyroid-stimulating hormone works in your body, how an imbalance can affect your overall health, and how a thyroid-stimulating hormone blood test can help provide insights into the cause of symptoms you may be experiencing.
What is thyroid stimulating hormone?
Thyroid-stimulating hormone (TSH), also known as thyrotropin, is a hormone produced in the pituitary gland that triggers your thyroid gland to produce and release hormones. Your thyroid gland is an important endocrine gland responsible for producing and releasing the hormones thyroxine (T4) and triiodothyronine (T3). You can find out more about what your thyroid gland does in our guide.
T4 and T3 hormones are essential for maintaining your body’s metabolic rate (the speed at which your body transforms the food you eat into energy) as well as maintaining:
- Your heart and digestive functions
- Muscle control
- Brain development
- Bone health
How are TSH levels controlled?
TSH levels are controlled by multiple hormones and glands in your endocrine system. This includes your hypothalamus (part of the brain that controls functions like your blood pressure, heart rate, temperature, and digestion as well as regulating hormones), your pituitary gland, thyroid-releasing hormone, thyroid stimulating hormone, T4 and T3. These glands and hormones work in conjunction on a feedback loop system to help keep your levels balanced in the following way:
- Your hypothalamus releases thyroid-releasing hormone (TRH) to trigger the release of TSH by your pituitary gland.
- TSH stimulates cells in your thyroid to release thyroid hormones (T4 and T3) into your bloodstream.
- Once T4 and T3 levels reach a certain level, they prevent the pituitary gland from producing more TSH.
- When T4 and T3 levels drop, the cycle starts over again.
This feedback loop means that if your thyroid gland produces abnormally high or low thyroid levels, it affects your TSH levels. Likewise, if your pituitary gland produces too much or too little TSH, this will impact the function of your thyroid.
It is more common for people experiencing abnormal TSH levels to have an issue with their thyroid gland than their pituitary gland.
Symptoms of low TSH levels
If you have low TSH levels, it is likely you will experience some of the following symptoms:
- Palpitations (rapid heartbeat)
- Feeling shaky
- Feeling anxious
- Unexplained weight loss with increased appetite
- Diarrhoea
- Changes to your vision and/or bulging eyes
- Thin, warm, and moist skin
- Goiter (a swelling on the neck from an enlarged thyroid gland)
- Irregular menstrual periods (in females)
If you are experiencing any of these symptoms it is important you speak to your doctor or book a private GP consultation to discuss possible causes of your symptoms.
Causes of low TSH levels
In most cases, low TSH levels are caused when your thyroid gland is making excess thyroid hormones. This condition is known as hyperthyroidism or an overactive thyroid. There are multiple conditions that can lead to hyperthyroidism, including Grave’s disease and thyroid nodules. Hyperthyroidism is a treatable condition, so it’s important you seek advice from your doctor.
In rare cases, low TSH levels can be caused by issues with your pituitary gland, such as a non-functioning pituitary adenoma.
Symptoms of high TSH levels
The symptoms of high TSH levels usually include:
- Fatigue
- Numbness and tingling in your hands
- Constipation
- Unexplained weight gain
- Depression
- Feeling cold all the time
- Low sex drive
- Frequent and heavy menstrual periods
Causes of high TSH levels
Too much TSH can indicate that your thyroid isn’t making enough thyroid hormone, this is known as hypothyroidism or underactive thyroid. It is important to seek medical advice if you are experiencing symptoms of high TSH levels as hypothyroidism is treatable.
In rare cases, an issue with your pituitary gland, such as a TSH-secreting pituitary adenoma, or rare genetic conditions can result in higher-than-normal TSH and thyroid hormone levels.
What happens if your TSH levels are abnormal
If your TSH results are abnormal, it does not necessarily mean you have a medical condition. Your doctor will consider other factors alongside your results when diagnosing a thyroid condition. This can include:
- Your age – TSH levels tend to be higher in older people, especially those over the age of 80.
- If you are pregnant – Pregnancy causes changes in your thyroid hormone. It is normal for TSH levels to be slightly lower than normal in the first trimester of your pregnancy, but they should increase as the pregnancy progresses.
- Severe illness – People who have an illness not related to their thyroid may have temporarily low TSH levels.
- Other thyroid test results – The results of other thyroid tests, such as free T4 and thyroid antibodies, can affect how your results are interpreted.
How can I test my TSH levels?
It is possible to test your TSH levels using a simple blood draw. A trained health assessment specialist will take a sample of blood from a vein in your arm and send it to a laboratory for testing.
Private thyroid hormone tests with Bluecrest Wellness
If you are concerned that your symptoms could be related to TSH or thyroid hormone levels, consider booking a private thyroid blood test at Bluecrest Wellness. Our thyroid function test analyses your TSH and T4 levels to provide you with insights into your thyroid health. It can be added to any of our full-body health assessment packages to offer comprehensive insights into your overall health and well-being.
We use the latest technologies in all of our tests to ensure accurate results and all can be booked at a time and location that’s convenient for you. In addition, every full health assessment comes with a comprehensive Results Report and free access to a 24/7 GP helpline for a year for complete peace of mind following your health assessment.
