Written by Pharmacist, Sherreen Cheah Shi Mun

What is Hyperthyroidism?


Also known as overactive thyroid, is a condition that occurs when the thyroid gland produces excessive amount of thyroid hormones. Thyroid hormones control the way the body uses energy, stay warm and keep the brain, heart, muscles, and other organs working. These processes are called metabolism. When the thyroid gland is overactive, every function of the body tends to speed up, which can cause a wide range of symptoms, including:


  • Nervousness, irritability, anxiety
  • Swollen thyroid
  • Increased sweating
  • Rapid heartbeat or palpitations
  • Shaking in hands and fingers
  • Weight loss despite increase in appetite
  • Difficulty sleeping
  • Skin thinning
  • Fine brittle hair
  • Muscle weakness, especially in the upper arms and thighs

What causes hyperthyroidism?


Hyperthyroidism has several causes, including:

  • Graves’ disease, an autoimmune disorder
  • Lumps (nodules) on the thyroid
  • Thyroiditis, inflammation of the thyroid
  • Consume too much iodine (either from foods or supplements) or take too much thyroid hormone medicine

Hyperthyroidism Diagnosis

The diagnosis of hyperthyroidism will be confirmed based on:

  • Symptoms
  • Physical exams
  • Blood tests to measure levels of thyroid hormones
  • Ultrasound scan of the thyroid can be used to diagnose lumps, or whether it is inflamed or overactive


The aim of treatment is to reduce and normalize the production of thyroid hormone in order to prevent long term health problems and to relieve symptoms.

Treatment will depend on the severity and underlying cause of hyperthyroidism, age, pregnancy, other conditions such as heart disease, and the potential side effects of the medication.


  • Medicines
  • Radioiodine therapy
  • Thyroid surgery

What should I avoid eating if I have hyperthyroidism?

People with Graves’ disease or other types of autoimmune thyroid disorder may be sensitive to harmful side effects from iodine.

Avoid eating excessive amounts of iodine-rich foods, such as

  • Iodized salt
  • Seaweed
  • Milk or other dairy products
  • Egg yolk

Taking iodine supplements may also cause or worsen the condition.



  1. Hyperthyroidism | American Thyroid Association [Internet]. American Thyroid Association. 2020 [cited 8 April 2020]. Available from: https://www.thyroid.org/hyperthyroidism/
  2. Hyperthyroidism – Symptoms and causes [Internet]. Mayo Clinic. 2020 [cited 8 April 2020]. Available from: https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-2 0373659
  3. Overactive thyroid (hyperthyroidism) [Internet]. nhs.uk. 2020 [cited 8 April 2020]. Available from: ​https://www.nhs.uk/conditions/overactive-thyroid-hyperthyroidism/
  4. Information H, Diseases E, Thyroid) H, Thyroid) H, Center T, Health N. Hyperthyroidism (Overactive Thyroid) | NIDDK [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases. 2020 [cited 8 April 2020]. Available from: https://www.niddk.nih.gov/health-information/endocrine-diseases/hyperthyroidism