Conditions
Hyperthyroidism: symptoms, tests and treatment
Hyperthyroidism is when your thyroid makes more hormone than your body needs. It causes a racing heart, nervousness, tremor, feeling hot, sweating and weight loss even when you eat more. It can’t be diagnosed from symptoms alone: you need a blood test. By video, the doctor evaluates you, gives you a lab order and, if it is confirmed, refers you to endocrinology and helps with symptoms.
Is it an emergency? Call 911.
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Fever with confusion, agitation or severe restlessness
- A very fast or irregular heartbeat with chest pain, shortness of breath or fainting
- Severe diarrhea with fever, a lot of shaking or heavy sweating
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At a glance
Hyperthyroidism
Common symptoms
- A racing, pounding or irregular heartbeat
- Nervousness, anxiety or irritability
- Shaky hands
- Feeling hot and sweating a lot
- Weight loss even though you are hungrier
- Tiredness and muscle weakness
- Trouble sleeping
- More frequent bowel movements
- Irregular periods
- A swollen neck (goiter)
- Other names
- Overactive thyroid · Graves’ disease
- Usual test
- Blood tests for TSH, free T4 and T3
- Treatment
- Antithyroid medicine, radioactive iodine or surgery, directed by endocrinology; a beta-blocker for symptoms, only when the medical evaluation calls for it
- Possible complication
- Thyroid storm, heart problems and osteoporosis
On this page(9)
What is hyperthyroidism?
The thyroid is a butterfly-shaped gland at the front of your neck. Its hormones control how your body uses energy. In hyperthyroidism, or overactive thyroid, it makes too much and everything speeds up.
According to the NIDDK, it affects about 1 in 100 people ages 12 and older in the United States, and it is more common in women and after age 60. The most common cause is Graves’ disease, an autoimmune condition. Other causes include thyroid nodules that make too much hormone, thyroid inflammation (thyroiditis, which can follow childbirth or a virus) and taking too much thyroid hormone.
It is the opposite of hypothyroidism, an underactive thyroid. If what you notice is unexplained weight loss, irregular periods or insomnia, see those guides too: they can have other causes.
How we help with hyperthyroidism by video
You see Dr. Diana Nieves Castro, MD, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. She asks about your symptoms, your periods, any family history of thyroid disease, whether you are or were recently pregnant, and which medicines and supplements you take.
We evaluate, diagnose and treat. We give you a lab order for TSH and thyroid hormones (free T4 and T3) at a lab near you, and go over the results with you in a follow-up visit. If it is confirmed, we refer you to endocrinology to start treating the cause, and for tests such as an iodine uptake scan if needed. In the meantime, if appropriate, the doctor prescribes a medicine to control the racing heart and tremor, and we send your prescription to your pharmacy.
We see adults and children of all ages. If the patient is under 21, a parent or legal guardian must be on camera for the whole visit and show photo ID.
Your doctor
Dr. Diana Nieves Castro, MD
General practice physician
Several years of emergency-department experience.
Founding Executive Director of The Health Initiative.
Your visit in 3 steps
Request a visit online 24/7 — we confirm your time by email or text See how our online doctor visit works.
Request your visit.
Book a visit and choose "Doctor visit". You pay by card when you request it.
See the doctor by video.
We send you a secure video link. It works on your phone, tablet or computer.
Get your plan.
You get a lab order and, if needed, a referral. If appropriate, the doctor prescribes and we send your prescription to your pharmacy.
What the visit costs
The evaluation is a US$79 doctor visit, with no membership. Reviewing the results of labs our doctor ordered is a US$49 follow-up visit. You pay by card when you request the visit, and you get a full refund if the visit can’t take place. We do not bill insurance; the lab and the pharmacy charge separately. See all prices.
Hyperthyroidism symptoms
According to MedlinePlus and the NIDDK, the most common symptoms are:
- A racing, pounding or irregular heartbeat
- Nervousness, anxiety or irritability
- Shaky hands
- Feeling hot and sweating a lot
- Weight loss even though you are hungrier
- Tiredness and muscle weakness
- Trouble sleeping
- More frequent bowel movements
- Irregular periods
- A swollen neck (goiter)
Tests and treatment
Tests. The NIDDK explains that hyperthyroidism can’t be diagnosed from symptoms alone, because they look like those of other conditions. MedlinePlus lists TSH, free T4 and T3, and sometimes antibodies and thyroid imaging.
Treating the cause. According to the NIDDK, there are three options: antithyroid medicines such as methimazole, radioactive iodine, or thyroid surgery. The endocrinologist decides with you. If the thyroid is removed or destroyed, you then need to take thyroid hormone for life.
Symptom relief. Beta-blockers help with a racing heart, tremor and nervousness while treatment takes effect. If appropriate, the doctor prescribes one.
If you are pregnant, the NIDDK warns that severe untreated hyperthyroidism is a risk for you and the baby. We do not provide pregnancy care: your OB-GYN and an endocrinologist should manage it.
If your eyes bulge, feel irritated or you see double, you need an in-person evaluation: Graves’ disease can affect the eyes. We refer you.
Complications
Without treatment, MedlinePlus explains that hyperthyroidism can cause heart problems such as an irregular heartbeat and heart failure, weak bones (osteoporosis) and eye problems. The most serious complication is thyroid storm, an emergency.
When to go to the ER
MedlinePlus explains that thyroid storm is a life-threatening emergency. For your safety, call 911 or go to the emergency room if you have hyperthyroidism and any of these signs. See when to go to the ER.
- Fever with confusion, agitation or severe restlessness
- A very fast or irregular heartbeat with chest pain, shortness of breath or fainting
- Severe diarrhea with fever, a lot of shaking or heavy sweating
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
What is the difference between hyperthyroidism and hypothyroidism?
Which blood tests check for hyperthyroidism?
Can I get treatment for hyperthyroidism by video?
Can hyperthyroidism be cured?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-02
Sources (3)
- Hyperthyroidism (Overactive Thyroid) (NIDDK, NIH) (opens in a new tab) (accessed 2026-10-02)
- Hyperthyroidism (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- Thyroid storm (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)