An overactive thyroid, also known as hyperthyroidism or thyrotoxicosis, is where the thyroid gland produces too much of the thyroid hormones.
The thyroid is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). It produces hormones that affect things such as your heart rate and body temperature.
Having too much of these hormones can cause unpleasant and potentially serious problems that may need treatment.
An overactive thyroid can affect anyone, but it's about 10 times more common in women than men, and typically happens between 20 and 40 years of age.
An overactive thyroid can cause a wide range of symptoms, including:
Find out more about the symptoms of an overactive thyroid.
See a GP if you have symptoms of an overactive thyroid.
They'll ask about your symptoms and if they think you might have a thyroid problem, they can arrange for a blood test to check how well your thyroid is working.
If the blood test shows that you have an overactive thyroid, you may be referred for further tests to identify the cause.
Find out more about how an overactive thyroid is diagnosed.
An overactive thyroid is usually treatable.
The main treatments are:
Each of these treatments has benefits and drawbacks. You'll usually see a specialist in hormonal conditions (endocrinologist) to discuss which treatment is best for you.
Find out more about how an overactive thyroid is treated.
There are several reasons why your thyroid can become overactive.
Find out more about the causes of an overactive thyroid.
An overactive thyroid can sometimes lead to further problems, particularly if it's not treated or well controlled.
Find out more about the complications of an overactive thyroid.