Hyperthyroidism: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Hyperthyroidism?
An endocrinologist, a doctor who treats hormone and gland problems, is the main doctor for hyperthyroidism. Your treatment plan is often made with this specialist. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is hyperthyroidism?
Hyperthyroidism, also called overactive thyroid, means the thyroid gland makes more thyroid hormones than your body needs. The thyroid is a small, butterfly-shaped gland in the front of your neck. Thyroid hormones control how the body uses energy. With too much of them, many body functions speed up.
Symptoms
Symptoms differ from person to person. They may include:
- Weight loss despite an increased appetite.
- A rapid or irregular heartbeat.
- Nervousness, anxiety, or irritability.
- Trouble sleeping.
- Tiredness or muscle weakness.
- Shaky hands (tremor).
- Sweating or trouble handling heat.
- Frequent bowel movements or diarrhea.
- Hair loss.
- Changes in menstrual periods, often lighter or less frequent.
- A goiter, an enlarged thyroid that may make your neck look swollen.
A large goiter can sometimes make it harder to breathe or swallow. People with autoimmune thyroid disease may also have pain behind the eyes, or swelling or bulging of the eyes.
Untreated, it can cause an irregular heartbeat that leads to blood clots, stroke, and heart failure. It can also thin the bones and cause fertility problems in women.
Causes and who gets it
Hyperthyroidism has several causes:
- Graves' disease, an autoimmune disorder in which your immune system attacks your thyroid and causes it to make too much hormone. This is the most common cause.
- Thyroid nodules, which are growths on your thyroid. They are usually not cancer, but they may become overactive.
- Thyroiditis, which is inflammation of the thyroid. It causes stored thyroid hormone to leak out.
- Too much iodine, which is found in some medicines, cough syrups, and seaweed-based supplements.
- Too much thyroid hormone medicine, taken by people with hypothyroidism, an underactive thyroid.
You are more likely to have it if you are a woman or are older than 60. A family history of thyroid disease or a pregnancy in the past 6 months also raises the risk.
How doctors diagnose it
Your doctor will ask about your health and do a physical exam. Symptoms alone cannot confirm hyperthyroidism. Many of them are the same as those of other diseases. So your doctor may use blood tests and imaging tests.
Blood tests check thyroid hormone levels (TSH, T4, and T3) and thyroid antibody levels. Hyperthyroidism usually shows high T4 and/or T3 and low TSH. Imaging tests include a thyroid ultrasound, a thyroid scan, or a radioactive iodine uptake test.
Treatment
No single treatment works for everyone. Treatment depends on the cause and how severe it is. It usually means medicines, radioiodine therapy, or thyroid surgery.
- Antithyroid medicines make the thyroid produce less hormone. They are the simplest treatment, but they are often not a permanent cure. You will probably need to take them for 1 to 2 years. In some cases, you might need them for several years. Side effects can include rashes, a drop in white blood cells, and, rarely, liver failure.
- Beta blockers can ease tremors, rapid heartbeat, and nervousness until other treatments work. They do not stop hormone production.
- Radioiodine therapy is a common and effective treatment. You take radioactive iodine by mouth as a capsule or liquid. It slowly destroys the thyroid cells that make hormone. Almost everyone who has it later develops hypothyroidism, an underactive thyroid. That is easier to treat and causes fewer long-term health problems. It is not used for women who are pregnant or breastfeeding.
- Surgery to remove part or most of the thyroid is used less often. It may be an option for people with large goiters, or pregnant women who cannot take antithyroid medicines. If the whole thyroid is removed, you will need thyroid hormone medicine for life.
If you take antithyroid medicine, call your doctor right away for yellow skin or eyes, a constant sore throat, or fever.
When to see a doctor
Many symptoms of hyperthyroidism are the same as those of other diseases, so a diagnosis cannot be based on symptoms alone. See a doctor for testing if you have a rapid or irregular heartbeat, weight loss despite an increased appetite, hand tremors, or a swollen neck.
Call 911 or go to the emergency room if you have chest pain, fainting, severe trouble breathing, or a sudden change in mental state.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can order first thyroid blood tests and follow your hormone levels over time. They can also coordinate your care with an endocrinologist.
Common questions
What is the most common cause of hyperthyroidism?
Graves' disease is the most common cause of hyperthyroidism. It is an autoimmune disorder. The immune system attacks the thyroid and makes it produce too much hormone.
Can hyperthyroidism be cured?
It depends on the treatment. Antithyroid medicines are often not a permanent cure. Radioiodine therapy slowly destroys the cells that make thyroid hormone. Almost everyone who has it later develops hypothyroidism, an underactive thyroid. That is easier to treat.
Can too much iodine cause hyperthyroidism?
Yes. Taking too much iodine can cause the thyroid to make too much thyroid hormone. Iodine is found in some medicines, cough syrups, and seaweed-based supplements. Ask your doctor which to avoid.
Sources
- MedlinePlus - Hyperthyroidism
- National Institute of Diabetes and Digestive and Kidney Diseases - Hyperthyroidism (Overactive Thyroid)
- American Thyroid Association - Hyperthyroidism
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
