Hyperthyroidism
A condition in which the thyroid produces too much hormone.
Definition
Hyperthyroidism occurs when the thyroid gland produces an excess of thyroid hormone, speeding up the body's metabolism. This can cause a rapid heartbeat, unintended weight loss, nervousness, and heat intolerance. Graves disease is the most common cause, but not all hyperthyroidism is Graves disease.
The Diagnostic Journey
A typical path patients take with Hyperthyroidism — from first symptoms to living with the condition. Click each stage to expand.
Many invisible illnesses begin with vague, intermittent symptoms such as fatigue, pain, or changes in weight or mood. Because these signs are non-specific and can come and go, they are frequently attributed to stress or overwork, which is one reason diagnosis is so often delayed.
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The History of the Thyroid: From Mystery Gland to Modern Medicine
How a small butterfly-shaped gland went from being a medical mystery to one of the most studied organs in the body.
What Is Graves Disease? A Comprehensive Overview
Everything you need to know about Graves Disease — from symptoms and causes to diagnosis and treatment options.
Related Glossary Terms
Sources & References
This page draws on trusted, authoritative health resources. For medical decisions, always consult a qualified healthcare professional.
- Hyperthyroidism (Overactive Thyroid)National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIHGovernment Health Agency
- Thyroid Information for PatientsAmerican Thyroid AssociationProfessional Medical Society
- Endocrine Diseases: ThyroidNational Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIHGovernment Health Agency
- Health Topics: Trusted Consumer Health InformationMedlinePlus, U.S. National Library of MedicineGovernment Health Agency
- Health Topics A-ZMedlinePlus, U.S. National Library of MedicineGovernment Health Agency
- Health Library: Diseases & ConditionsCleveland ClinicAcademic Medical Center
Content Review
- Last Reviewed
- July 2026
- Last Updated
- July 2026
- Content Type
- Educational Documentary Companion
- Evidence Standard
- Evidence-Informed
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