What happens if hypothyroidism is not treated?

An underactive thyroid does not produce enough hormone to support the body’s usual pace. Untreated symptoms may include daytime sleepiness, low mood, slowed thinking, cold hands and feet, cold intolerance, constipation, dry skin and muscle aches. Some people develop a goitre, which is an enlargement in the neck caused by changes in the thyroid. Cholesterol and heart function may also be affected, and untreated disease can be particularly serious during infection, severe illness or exposure to cold.

Symptoms often build gradually, so they can be mistaken for stress, poor sleep or ageing. A blood test is needed to confirm the diagnosis and distinguish it from other causes of tiredness.

Arrange a medical assessment if symptoms persist or if a previous thyroid result was abnormal. Thyroid Hormone Replacement is commonly used when the thyroid cannot make enough hormone. The dose is tailored to you and checked with follow-up blood tests; it may need adjustment during pregnancy, after major illness or when other medicines change. Take it exactly as prescribed and tell your clinician about supplements, heart problems and pregnancy plans. Avoid changing the dose because of a single good or bad day.

Seek urgent help for severe drowsiness, confusion, unusually slow breathing, a very low body temperature, fainting or chest pain. Contact a clinician soon if tiredness is worsening, a neck swelling is growing, swallowing becomes difficult, or constipation, muscle aches or cold intolerance are interfering with everyday activities.

Ask which thyroid tests you need, when results should be repeated, how to take replacement hormone around food or supplements, and which symptoms suggest the dose is too low or too high. Ask how pregnancy or another illness could change your monitoring.