Hyperthyroidism (Overactive Thyroid)

What is hyperthyroidism?

Hyperthyroidism also known as overactive thyroid is a when the thyroid gland produces too much thyroid hormone. Read our page on thyroid disease to learn more about thyroid and thyroid gland.

Causes of hyperthyroidism

The some common and not so common causes of overactive thyroid.

Common causes

  • Graves’ disease.
  • Thyroid nodules.
  • Thyroiditis (inflammation of the thyroid).

Uncommon causes

  • Non-cancerous tumour of the pituitary gland.
  • Taking too much iodine.  
  • Taking too much of anti-thyroid drug.

What are the symptoms of hyperthyroidism?

Symptoms of hyperthyroidism can be mild or severe and while an overactive thyroid can cause  a lot of symptoms,  it is unlikely that you will experience all of them.

  • Anxiety
  • Nervousness
  • Irritability
  • Dizziness
  • Shortness of breath
  • Mood swings
  • Muscle weakness
  • Strong feeling of hunger
  • Diarrhoea
  • Frequent urination
  • Constantly feeling thirsty
  • Hyperactivity – difficulty staying still.
  • Trouble sleeping
  • Feeling tired all the time
  • Inability to tolerate heat
  • Itchiness
  • Loss of interest in sex

What are the signs of hyperthyroidism?

  • Goitre-This is a swelling in the neck that results from an enlarged thyroid gland.
  • Weight loss- This is despite the strong feeling of hunger.
  • Hair loss or thinning of the hair.
  • Increased heart rate (palpitations)
  • Shaky hands
  • Warm moist skin
  • Fragile nails
  • Hives (urticaria)
  • Eye problems

How is hyperthyroidism diagnosed?

Read the diagnosis section of our thyroid disease post.

Treatment of hyperthyroidism

The treatment your doctor prescribes depends on factors such as the type of hyperthyroidism, the severity, age, whether or not you are pregnant or if you planning for a baby. ; or radioactive iodine. Each treatment has advantages and disadvantages, but your doctor will weight each option and choose the most suitable treatment for you.


Beta blockers are usually used to reduce the symptoms of hypothyroidism while waiting for other treatments (Antithyroid drugs and radioactive iodine) to start working.

Antithyroid medications

Antithyroid drugs are the first line treatment and preferred treatment for children, and They work by reducing the production of thyroid hormones. Carbimazole is the usual drug prescribed though your doctor can prescribe you Propylthiouracil (PTU) if you cannot take Carbimazole due to side effects or if you plan to become pregnant or are pregnant. Do not stop taking these tablets unless instructed by your doctor.

Radioiodine therapy

To do this, you ingest radioactive iodine (I-131) and the thyroid absorbs it into the thyroid cell in the same way it would absorb the normal iodine when synthesizing thyroid hormones. In the thyroid cell, radioactive destroys the overactive thyroid cells over time. This causes your thyroid gland to reduce in size and the symptoms improves over weeks or months. You may require thyroid hormones replacement with normal amounts of thyroid hormones.

Side effect of radioiodine therapy includes tenderness in the neck , temporary increase in thyroid hormones, temporary worsening of Graves’ ophthalmopathy, small increased risk of new Graves’ ophthalmopathy so radioiodine therapy may not be recommended if you already have moderate to severe eye problems or if you are pregnant or breast-feeding.

Thyroid surgery

Surgery can be done to remove all or part of the thyroid gland. This surgery is called thyroidectomy or subtotal thyroidectomy . Surgery is usually done on people with severe hyperthyroidism or those with large goitre. Some patients will require lifelong levothyroxine after surgery.

The risks of this thyroid surgery is include that the nerve that controls your vocal cords and the parathyroid glands could be damaged.

Frequently asked questions

Can hyperthyroidism cause weight gain?

Hyperthyroidism causes weight loss even with the strong feeling of hunger. However a few people may gain weight.

Can hyperthyroidism cause high blood pressure?

Yes. Hyperthyroidism can cause you to have high blood pressure.

Is hyperthyroidism curable?

Yes, see treatment of hyperthyroidism above.

Can hyperthyroidism cause acne?

There is no evidence that hyperthyroidism causes acne.

Can hyperthyroidism cause headaches?

There is no evidence that hyperthyroidism causes headaches.

Can hyperthyroidism cause hair loss?

Yes it can cause hair loss. See signs of hyperthyroidism above.

Is hyperthyroidism a disease

Yes it is a disease that causes you to produce too much thyroid hormone.

Can hyperthyroidism kill you?

Yes. Untreated hyperthyroidism can rarely cause thyroid storm which can be fatal.

Can hyperthyroidism cause dizziness?

Yes hyperthyroidism can cause dizziness.

Can hyperthyroidism cause shortness of breath?

Yes hyperthyroidism can cause shortness of breath.

Is hyperthyroidism an autoimmune disease?

Graves’ disease which is the most common cause of hyperthyroidism is an autoimmune disease.

Is hyperthyroidism dangerous?

When left untreated, hyperthyroidism can lead to a dangerous condition called thyroid storm.

Is hyperthyroidism hereditary?

Hyperthyroidism is often hereditary.

Shopping Basket
Scroll to Top