Hyperthyroidism (Overactive Thyroid)

A condition where the thyroid gland makes too much thyroid hormone, speeding up the body's processes.

ThyroidHormonesLast updated: 21 October 2026

Quick Summary

Primary Symptoms

Weight loss, fast heartbeat, anxiety, shaking hands, sweating, feeling hot, frequent bowel movements and trouble sleeping.

Common Treatments

Antithyroid medicines such as carbimazole, radioactive iodine or surgery, plus beta blockers for symptoms.

Risk Factors

Graves' disease, thyroid nodules, family history, being female and thyroid inflammation.

OverviewSymptomsCausesTreatmentFAQ

Overview

When the thyroid is overactive, metabolism speeds up, affecting the heart, weight, mood and energy.

The most common cause is Graves' disease, an autoimmune condition that can also affect the eyes.

Symptoms

Fast heartbeat

Palpitations or an irregular heartbeat.

Weight loss

Despite a normal or increased appetite.

Shaking hands

With sweating and feeling hot.

Anxiety and irritability

Difficulty sleeping.

Causes & Risk Factors

Biological Causes

Graves' disease (antibodies stimulate the thyroid), overactive thyroid nodules, or inflammation releasing stored hormone.

Key Risk Factors

  • Female sex More common in women.
  • Family history Of thyroid or autoimmune disease.
  • Smoking Increases the risk of Graves' eye disease.

Management & Treatment

01. Antithyroid medicines

Carbimazole or methimazole reduce hormone production.

02. Beta blockers

Such as propranolol to ease symptoms.

03. Radioactive iodine or surgery

For long-term control in some people.

Frequently Asked Questions

Is it serious?
It can affect the heart and bones if untreated, so treatment matters.
Can it affect the eyes?
Graves' disease can cause bulging, dry or irritated eyes.
Is treatment safe in pregnancy?
It needs specialist care; some medicines are preferred.

Sources and further reading

Last updated 21 October 2026. For more detail, see these trusted health organisations.