Overactive Thyroid: A Beginner-Friendly Start
Overactive Thyroid: the few things that matter most, and the mistakes that catch people out early.
Hyperthyroidism: the thyroid producing too much hormone, speeding up many body processes.
Key takeaways
- Main test: low TSH, with high T4 or T3
- Most common cause: Graves' disease
- Most useful single change: See your doctor about unexplained weight loss with palpitations or tremor.
- Commonest mistake: Putting palpitations and anxiety down to stress without a thyroid test.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
Why bother
It causes weight loss, palpitations and anxiety that are often put down to stress, and it carries real heart and bone risks if untreated.
Start here
Two to start. There is no prize for doing all of it in week one.
- See your doctor about unexplained weight loss with palpitations or tremor
- Report eye symptoms, which need assessment by an eye doctor in Graves' disease
Then add these
Once the first two are automatic, these are worth adding.
- Take antithyroid medicine exactly as prescribed
- Quit smoking, which considerably worsens thyroid eye disease
The numbers, in one place
| Measure | Figure |
|---|---|
| Main test | low TSH, with high T4 or T3 |
| Most common cause | Graves' disease |
| Treatments | antithyroid medicines, radioactive iodine, or surgery |
| Methimazole warning | sore throat or fever needs an urgent blood count |
| Associated risks | atrial fibrillation and osteoporosis |
Common early mistakes
- Putting palpitations and anxiety down to stress without a thyroid test
- Ignoring a sore throat or fever while taking methimazole
- Stopping treatment when symptoms improve
Related topics
- Diabetes Remission: What the Evidence Actually Says (Diabetes)
- Testosterone: What the Evidence Actually Says (Men's Health)
- Vitamin D: What the Evidence Actually Says (Nutrition)
- Rate of Weight Loss: Sorting the Evidence From the Noise (Weight Management)
Where to go next
- Overactive Thyroid: The Quick Reference
- Overactive Thyroid: Sorting the Evidence From the Noise
- Overactive Thyroid — the reference entry
- Thyroid and Hormones: The Complete Guide
- What the Guidance Really Says About Thyroid Function Tests
- Thyroid Lumps: What Published Guidance Supports
When to speak to a doctor
Contact your doctor the same day for a sore throat, mouth sores, fever or bruising while taking methimazole or propylthiouracil — these can indicate a dangerous drop in white blood cells and need an immediate blood count. Call 911 for fever with agitation, a very rapid heart rate, vomiting and confusion, which can indicate thyroid storm. Report double vision or eye pain to your doctor urgently.
Where this comes from
- American Thyroid Association — Hyperthyroidism (Overactive)
- National Institute of Diabetes and Digestive and Kidney Diseases — Hyperthyroidism (Overactive Thyroid)
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
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