Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Symptoms - Overactive thyroid (hyperthyroidism)

An overactive thyroid is also known as hyperthyroidism. It is where the thyroid gland produces too much of the thyroid hormones.

The thyroid is found at the front of the neck. It produces hormones that affect things such as your heart rate and body temperature.

Extra levels of these hormones can cause unpleasant and serious problems that may need treatment.

An overactive thyroid can cause a wide range of symptoms. But it's unlikely you'll experience all of them.

The symptoms may develop gradually or suddenly. For some people they can be mild, but for others they can be severe and significantly affect their life.

Symptoms of an overactive thyroid

Symptoms of an overactive thyroid can include:

  • nervousness, anxiety and irritability
  • hyperactivity - you may find it hard to stay still and feel full of nervous energy
  • mood swings
  • difficulty sleeping
  • feeling tired all the time
  • sensitivity to heat
  • muscle weakness
  • diarrhoea
  • needing to pee more often than usual
  • persistent thirst
  • itchiness
  • loss of interest in sex

Common signs

An overactive thyroid can also cause the following physical signs:

  • a swelling in your neck caused by an enlarged thyroid gland (goitre)
  • an irregular or unusually fast heart rate (palpitations)
  • twitching or trembling
  • warm skin and excessive sweating
  • red palms of your hands
  • loose nails
  • a raised, itchy rash - known as hives (urticaria)
  • patchy hair loss or thinning
  • weight loss - often despite an increased appetite
  • eye problems, such as redness, dryness or vision problems

Talk to your GP if you have symptoms of an overactive thyroid. It might be useful to make a list of all your symptoms and show it to your GP.

These symptoms can have many causes. But a simple blood test can often help find out if they're caused by a problem with your thyroid.

How an overactive thyroid is diagnosed

Content supplied by the NHS and adapted for Ireland by the HSE

Slaintecare logo
This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 14 March 2021
Next review due: 14 March 2024