Overactive Thyroid (Hyperthyroidism) - Symptoms (NHS)

Tier 1: Established: peer-reviewed research or government health authority
Publisher: National Health Service · Published: August 11, 2026 · Accessed: August 11, 2026

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Claims this source supports

• An overactive thyroid (hyperthyroidism) can cause a wide range of symptoms that may develop gradually or suddenly: nervousness, anxiety and irritability; hyperactivity; mood swings; difficulty sleeping; feeling tired all the time; sensitivity to heat; an irregular or unusually fast heart rate; and weight loss.
• Loss of interest in sex is listed among hyperthyroidism symptoms - the thyroid flag in NHS guidance is a change in desire in the context of a broader symptom cluster, not an increase on its own.
• See a GP if you have symptoms or signs of an overactive thyroid; a blood test can often help determine whether symptoms are caused by a thyroid problem.