Hypothyroidism vs Hyperthyroidism - What's the difference?

by imedical

Thursday August 18th 2022

Hypothyroidism vs Hyperthyroidism - What's the difference?-Thyroid-Issues-02a

Diagnosis is essential as it can affect every body system.

Thyroid disease is relatively common and runs in families yet is often overlooked. It affects women more than men, and women are ten times more likely to have thyroid issues. 1.

What is the thyroid?

The thyroid gland is the butterfly-shaped gland at the base of your neck.

It regulates many metabolic processes of vital body functions, including growth and energy expenditure, as thyroid hormones convert oxygen and calories into energy. These metabolic processes control how fast or slow your brain works and your heart, liver, muscles, and other vital organs.

What tests are available?

To find out if you have a thyroid condition, the Australian Thyroid Foundation recommend diagnosis using biochemical pathology testing - TSH, T4, T3 and Thyroid Antibodies.

Thyroid blood tests are available individually or as a full thyroid panel giving you and your doctor a comprehensive view of your thyroid function.

Hypothyroidism vs. Hyperthyroidism

How Do They Differ? In both cases, swelling in your neck is caused by an enlarged thyroid gland (goitre).

Below is a list of the signs and symptoms of Hypothyroidism (unactive thyroid) and Hyperthyroidism (overactive thyroid).


The symptoms of An underactive thyroid may develop gradually or suddenly.

Signs and symptoms of an unactive thyroid may include:

  • Lethargy and fatigue.
  • Depression and Anxiety
  • Impaired memory, Brain fog or Reduced concentration.
  • Unusual weight gain.
  • Dry skin and hair loss.
  • Constipation.
  • Increased sensitivity to cold.
  • Muscle aches, weakness and muscle cramps.
  • Menstrual and fertility issues.
  • Enlarged thyroid gland (goitre)
  • Elevated blood cholesterol levels

Read more on the symptoms of an Underactive Thyroid.

Hypothyroidism is unlikely to disappear, requiring you to take medication for the rest of your life. As each case differs, you should speak with your doctor about what to expect.


Just like in Hypothyroidism, the symptoms may develop gradually or suddenly. You may not experience all of these; they can be mild or severe.

Signs and symptoms of an overactive thyroid may include:

  • nervousness, anxiety and irritability
  • heart palpitations - irregular or fast heart rate
  • mood swings
  • difficulty sleeping
  • feeling tired all the time
  • sensitivity to heat
  • muscle weakness, twitching or trembling
  • a raised, itchy rash
  • unexpected weight loss
  • eye problems, including dryness or vision problems
  • diarrhoea and the needing to pee more often than usual
  • persistent thirst
  • itchiness

Hyperthyroidism is not necessarily permanent. If hyperthyroidism returns after you stop taking medication, your doctor may recommend removing your thyroid, as is the case if you experience side effects from medication.

Surgery and radioactive iodine can stop Hyperthyroidism, but you could develop Hypothyroidism after these treatments.

How are thyroid problems diagnosed?

Your doctor's diagnosis will be based on your symptoms, your blood test results, and possibly an ultrasound scan of your thyroid gland.

In the case of Hyperthyroidism, a thyroid function blood test is required, and the test checks the levels of:

Your thyroid hormone levels will be gauged by what is expected at your age. A low TSH and high T3 and T4 usually mean you suffer from an overactive thyroid.

Doctors may refer to these measurements as "free" T3 and T4 (FT3 and FT4).

Check your thyroid levels.

Private blood testing is now readily available, enabling you to take a proactive interest in your health. If you are concerned about changes in your health or wish to have the data for a second opinion, you can order thyroid tests in Australia online for testing at your nearest pathology lab.

Read more - Ten reasons to have your thyroid checked

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