Hyperthyroidism is also known as an overactive thyroid (or sometimes thyrotoxicosis). The thyroid gland is found in the neck and is responsible for the production of the chemical Thyroxine which controls energy levels. Hyperthyroidism is when too much of this chemical is produced. Read more for an explanation of this condition, the symptoms and the treatment that can help.

What is an Overactive Thyroid Gland?

The thyroid gland is found in the neck and produces the hormone Thyroxine. This hormone controls the metabolic rate which affects things like temperature and heart rate, as well as turning food into energy.

An overactive thyroid produces too much of this hormone, resulting in an increased metabolism.

There are several causes of an overactive thyroid which can include Grave's disease which is an autoimmune disease where the immune system attacks the thyroid gland. Another cause can be nodules on the thyroid gland which contain abnormal thyroid tissue which affects hormone production. Taking iodine supplements can increase thyroid activity as the body uses iodine to make thyroxine. Very rarely, some medications (especially for arrhythmia) and also a thyroid cancer can increase thyroid activity.

It is also possible to have an underactive thyroid (known as hypothyroidism) where not enough of the hormone thyroxine is produced. This tends to lead to fatigue, depression and weight gain as well as other symptoms.

Symptoms of Hyperthyroidism

Here is a list of symptoms which may be present in people with hyperthyroidism. It is an extensive list and it is unlikely that any one individual would suffer all of these symptoms. However, if you experience several of these symptoms together, it is worth speaking to your Doctor.

  • Hyperactivity
  • Weight loss
  • Mood swings
  • Difficulty sleeping
  • Increased appetite
  • Fatigue
  • Reduced sex drive
  • Light or infrequent periods
  • Infertility
  • Muscle weakness
  • Needing to urinate and pass stools more frequently
  • Heat sensitivity
  • Excess sweating
  • A swelling in the neck (goitre)
  • Rapid heart rate
  • Tremors (shaking)
  • Itching skin
  • Patchy hair loss

Hyperthyroidism is diagnosed with a blood test which looks at the levels of thyroxine and also the thyroid stimulating hormone (TSH).


Treatment of an overactive thyroid aims to return the levels of thyroxine production to normal.

In mild cases (with few or even no symptoms) your Doctor may decide not to provide any treatment initially and instead to monitor your condition via regular blood tests. In many cases, the hormone levels will return to normal on their own.

In more moderate to severe cases, you will be referred for specialist treatment. This may include options such as:

Thionamides (carbimazole and propylthiouracil) are medications which reduce the production of thyroxine. You will need to take this form of medication for at least 6-8 weeks before you start to notice a difference.

once your hormone production has stabilised then your Doctor may gradually reduce your dosage.

Rare side-effects include nausea, a skin rash, achy joints and itchy skin. In some very rare cases, Thionamides have been known to cause a condition called agranulocytosis which is a sudden drop in white blood cells. This is a serious condition as it lowers the bodies immune system. If you notice any symptoms of fever, a sore throat, mouth ulcers or any other signs of infections, visit your Doctor immediately.

Beta Blockers are sometimes prescribed whilst your thyroid is brought back under control. These can help to reduce some of the symptoms such as a tremor and hyperactivity.

Radioiodine treatment is a form of radiotherapy which can be used to treat most types of hyperthyroidism. It works by shrinking the thyroid so that it produces fewer hormones.

Surgery is sometimes performed in severe cases to remove part or all of the thyroid gland. This is known as a partial or full thyroidectomy. It is important that the right amount of the thyroid gland is removed as taking away too much can result in an underactive thyroid!

This is a permanent treatment option and is used on those whose thyroid has swollen and is causing neck problems.

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Hypothyroidism is also known as an underactive thyroid gland. The thyroid gland is found in the neck and produces the hormone thyroxine which controls how much energy your body is using....