Overview - Overactive thyroid (hyperthyroidism)

An overactive thyroid can cause a wide range of symptoms, including: nervousness, anxiety and irritability mood swings difficulty sleeping persistent tiredness and weakness sensitivity to heat swelling in your neck from an enlarged thyroid gland (goitre) an irregular and/or unusually fast heart rate (palpitations) twitching or trembling weight loss 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: medicine that stops your thyroid producing too much of the thyroid hormones radioiodine treatment – where a type of radiotherapy is used to destroy cells in the thyroid, reducing its ability to produce thyroid hormones surgery to remove some or all of your thyroid, so that it no longer produces thyroid hormones 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. These include: Graves' disease – an autoimmune condition where the immune system produces antibodies that cause the thyroid to produce too much thyroid hormone (about 4 in every 5 people with an overactive thyroid have Graves' disease) lumps (nodules) on the thyroid – this extra thyroid tissue can produce thyroid hormones, causing your levels to be too high some medicines such as amiodarone, which can be used to treat an irregular heartbeat (arrhythmia) 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. These include: eye problems – such as eye irritation, double vision or bulging eyes pregnancy complications – such as pre-eclampsia , premature birth or miscarriage a thyroid storm – a sudden and life-threatening flare-up of symptoms Find out more about the complications of an overactive thyroid

British Thyroid Foundation: help and support if you have an overactive thyroid