Does hyperthyroidism cause unintentional weight loss?

Excess thyroid hormone can speed up metabolism and increase heat production, bowel activity, and appetite. Some people lose weight even while eating more than usual; others notice reduced appetite. Sweating, heat intolerance, tremor, palpitations, nervousness, and sleep problems may occur alongside the change. Weight loss has many possible causes, so it does not by itself show that thyroid overactivity is responsible.

Arrange a medical appointment when weight is falling without a planned change in eating or activity, especially if you also have a racing heartbeat, shaking, or heat intolerance. Record your weight trend, appetite, bowel changes, sleep, and any medicines or supplements. A clinician may examine you and order thyroid blood tests, while also considering other explanations. Maintain regular meals and fluids, and avoid starting restrictive diets while the cause is being assessed.

Seek urgent help if weight loss occurs with severe weakness, fainting, confusion, chest pain, severe breathlessness, persistent vomiting, or a very fast heartbeat. Arrange prompt review when you cannot keep fluids down, are becoming dehydrated, or the change is accompanied by marked agitation or fever.

Could thyroid overactivity explain my weight change and other symptoms? Which blood tests will check this? Should I change my diet while waiting for results? What warning signs mean I should seek urgent help?