How is hypothyroidism treated?

An underactive thyroid does not make enough thyroid hormone for the body’s needs. This may contribute to cold intolerance, cold hands and feet, constipation, daytime sleepiness or muscle aches. Blood tests help confirm the diagnosis and provide a baseline for treatment.

[Thyroid Hormone Replacement](/treatments/medical-management/thyroid-hormone-replacement/) supplies the hormone in a tablet. The dose is individual: age, pregnancy, heart health, other medicines and the cause of the thyroid problem can all affect the plan.

Take the tablet consistently in the way your clinician or pharmacist explains. Some foods, supplements and medicines can reduce absorption, so mention calcium, iron, antacids and other regular products before changing the schedule. Do not alter the dose because you feel tired or better without checking first.

Blood tests after starting or changing treatment show whether the dose needs adjustment. Once levels are stable, follow-up remains useful, especially after pregnancy, major illness or a change in medicines. A swollen thyroid, called a [Goitre](/conditions/goitre/), may need separate assessment.

Arrange a review if tiredness, bowel changes, cold sensitivity or aches persist, or if you develop palpitations, tremor, sweating or unexplained weight change after a dose change. Seek urgent help for chest pain, severe breathlessness, fainting or profound drowsiness with confusion.

When should I take my tablet in relation to breakfast and supplements? When is my next blood test? Could another medicine affect absorption? What should I do if I miss a dose or become pregnant?