10 Early Signs Of Hyperthyroidism

Hyperthyroidism (overactive thyroid) occurs when your thyroid produces too much hormone. It can be simple to diagnose and there are several effective treatment options, but diagnosis and treatment can be delayed when symptoms are ignored or mistaken for other conditions.

Hyperthyroidism can lead to serious health problems when left untreated, so it’s important to know which signs and symptoms to look out for.

Have you considered clinical trials for Hyperthyroidism?

We make it easy for you to participate in a clinical trial for Hyperthyroidism, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is the thyroid gland and how does it work?

Your thyroid is a small gland in your neck that produces and secretes two hormones into your bloodstream: triiodothyronine (T3) and thyroxine (T4). These hormones keep your brain, heart, digestive system, muscles, and organs working as they should.

The pituitary gland controls the production of T3 and T4 in your thyroid by producing its own hormone, thyroid-stimulating hormone (TSH). Part of your brain called the hypothalamus produces thyrotropin-releasing hormone (TRH) which stimulates the release of TSH. This network is known as the hypothalamic-pituitary-thyroid axis.

What is hyperthyroidism?

Hyperthyroidism occurs when your thyroid produces too much T3 or T4 hormone, or too much of both. When working correctly, your thyroid gland only produces the hormones needed to keep your body’s metabolism in balance.

The opposite occurs with hypothyroidism, a condition where the thyroid doesn’t produce enough hormone.

How common is hyperthyroidism in the US?

Thyroid conditions are very common in the US — more than 12%¹ of the US population (20 million Americans) suffers from hyperthyroidism or hypothyroidism. 60%¹ are unaware they have a thyroid condition.

Hyperthyroidism is less common in the US than hypothyroidism, affecting 1.3%² of Americans over the age of 12.

Hyperthyroidism risk factors

Several factors increase your risk of hyperthyroidism, including:

  • Age (people over the age of 60 are more likely to have hyperthyroidism)

  • Sex (hyperthyroidism is more common in women than men)

  • Family history of thyroid disease

  • Recent pregnancy

  • High iodine intake (through diet or medication)

  • Having an autoimmune disease (like type 1 diabetes or lupus)

Common signs and symptoms of hyperthyroidism

Here are the common symptoms of hyperthyroidism you should know about:

Rapid heart rate (tachycardia)

When your thyroid overproduces hormones, your heart rate³ may rise to keep up with your increased metabolism. You might notice your heart beating rapidly even when resting, and it can rise to a higher-than-normal level when exercising.

Irregular heart rate (atrial fibrillation)

Hyperthyroidism can also cause your heart to beat irregularly and erratically. You might experience dizziness, shortness of breath, and a “fluttering” sensation in your chest.

This is dangerous if left untreated as your heart cannot effectively distribute blood through your body and it increases your risk of stroke.

Weight loss

Hyperthyroidism increases many body functions, including your metabolism. When your metabolism rises, your body burns more calories so you might experience increased appetite and unintentional weight loss.


Many people with hyperthyroidism experience unexplained anxiety,⁴ a mood disorder usually characterized by intense feelings of worry and concern, “butterflies” in the stomach, difficulty concentrating, nausea, rapid heartbeat, shortness of breath, and light-headedness.

Excessive sweating 

Thyroid hormones control the production of the energy molecule adenosine triphosphate (ATP). When your thyroid produces hormones correctly, your body temperature is regulated. Hyperthyroidism, however, leads to overproduction of ATP and causes you to overheat. You might notice yourself sweating more than usual as your body tries to regulate its temperature.

High blood sugar

Hyperthyroidism promotes hyperglycemia (high blood sugar) as it causes your body to produce more glucose. The condition also increases insulin resistance, making your cells less effective at removing glucose from your blood.

A review⁵ found that hyperthyroidism speeds up the metabolism of insulin and raises blood sugar levels in people with diabetes who take insulin shots. As a result, the condition was found to increase the amount of insulin needed in people who are diabetic, generally making blood sugar levels more challenging to control.


Since hyperthyroidism speeds up your body’s processes, you might assume it would help you feel more energetic and awake. In contrast, many people with hyperthyroidism experience extreme tiredness that impacts their day-to-day life. Fatigue in people with hyperthyroidism can also be worsened by other symptoms, such as difficulty sleeping, night sweats, and anxiety.


A large lump at the front of your neck known as a “goiter” is a common hyperthyroidism symptom caused by swelling of your thyroid gland. Apart from the obvious lump, you might also have other symptoms including a cough, hoarse voice, difficulty swallowing, and tightness in your throat.


Hyperthyroidism causes every cell in your body to produce more energy, so your nerves become over-stimulated which can cause mild tremors. The tremors are usually minimal, but as hyperthyroidism progresses, they may become more noticeable. For example, you might find it challenging to hold or pour a glass of water.


Having difficulty getting a good night’s sleep is a possible hyperthyroidism symptom. Insomnia can be caused by other signs and symptoms of the condition, including night sweats, rapid or irregular heart rate, and anxiety.

Hair loss

If you have severe or prolonged hyperthyroidism, you may experience hair loss. Hair loss occurs when more hair than usual enters the shedding phase (telogen effluvium). Hyperthyroidism-related hair loss is diffuse, meaning it occurs all over your head instead of in patches.

Hair loss can be triggered by many other things, including iron deficiency and stress, so you might experience hair loss alongside other hyperthyroidism symptoms.

How do doctors diagnose hyperthyroidism?

To diagnose hyperthyroidism, your doctor will take a close look at your personal and family medical history and perform a physical examination. They will also ask you about the symptoms you are experiencing, such as rapid heart rate, insomnia, and unexplained weight loss.

Your doctor will arrange for you to have a blood test to assess the levels of certain hormones in your blood. These tests include:

TSH level test

Since TSH controls how the thyroid gland produces hormones, testing TSH levels in your blood can help diagnose hyperthyroidism. You might have hyperthyroidism if your TSH levels are unusually low.

T3 test 

Having too much T3 hormone in your blood suggests you might have hyperthyroidism.

T4 test 

Carrying out a T4 test alongside a T3 test can accurately determine if you have hyperthyroidism. A high amount of T4 hormone in your blood indicates that your thyroid is overactive, particularly when coupled with a high T3 hormone reading.

Thyroid antibodies test

A thyroid antibodies test can be used to diagnose or rule out an autoimmune disease like Grave’s disease or Hashimoto’s thyroiditis that’s affecting your thyroid. This test is usually carried out after other tests confirm your thyroid hormone levels are abnormal.

Thyroid scan and uptake test

A thyroid scan and uptake test allow a medical professional to examine the size, structure, and function of your thyroid gland. You’ll be asked to swallow a pill containing a small quantity of a radioactive substance or have an injection. Once your thyroid has had time to absorb the radioactive substance, a scan is carried out to reveal how your thyroid is functioning.

How is hyperthyroidism treated?

After a hyperthyroidism diagnosis, your doctor can recommend treatments to help your thyroid function return to normal, reducing your symptoms. They may refer you to an endocrinologist, a hormone specialist, to take over your treatment.

Hyperthyroidism treatments include:


Your doctor or endocrinologist may prescribe a medication that helps return your thyroid hormone production to normal levels. Methimazole (Tapazole) is commonly prescribed to treat hyperthyroidism. Taken as a tablet three times a day, methimazole works by preventing the thyroid from producing new hormones.

Beta-blockers like atenolol, propanol, and metoprolol can help decrease symptoms of hyperthyroidism, including fast heart rate, tremors, and anxiety.

Radioactive iodine

Radioactive iodine destroys the cells that produce thyroid hormones. This treatment can cause side effects, like sore throat, dry mouth, or dry eyes.


Surgery to treat hyperthyroidism involves the removal of your thyroid gland or a section of it. Your thyroid plays an important role in your body function, so you may need to take thyroid supplements for the rest of your life.

Diet changes 

No specific diet is recommended to treat hyperthyroidism, but consuming some foods as part of a balanced, healthy diet can help.

Try to consume:

  • Low-iodine food and drinks (black coffee, vegetable oils, herbs and spices, non-iodized salt)

  • Cruciferous vegetables (kale, Brussel sprouts, collard greens, cabbages)

  • Selenium-rich foods (shrimp, Brazil nuts, tuna, fortified cereals, beef)

  • Iron-rich foods (dark chocolate, raisins, fortified cereals, oysters)

When to speak to a doctor about hyperthyroidism

Get medical help right away if you have any of the following symptoms:

  • Loss of consciousness

  • Seizures

  • Shortness of breath

  • Atrial fibrillation (irregular heartbeat)

  • Fast heart rate

  • Persistent sweating

  • Confusion

Undiagnosed hyperthyroidism can lead to atrial fibrillation, which can cause congestive heart failure and stroke. Other severe conditions caused by untreated hyperthyroidism include:

  • Grave’s ophthalmopathy

  • Thyroid storm

  • Pregnancy complications, including low birth weight, premature birth, and preeclampsia

  • Bone loss

Be aware of common hyperthyroidism symptoms. If they persist, make an appointment to speak to your doctor.

The lowdown

Left undiagnosed or untreated, hyperthyroidism can lead to severe health complications. Many hyperthyroidism symptoms, including unexplained weight loss, fatigue, and hair loss are easily mistaken for other health conditions, causing some people to live with the condition not knowing they have it.

Hyperthyroidism is diagnosed by looking at your personal and family medical history and performing a physical examination. Other investigations include a blood test and a thyroid scan and uptake test. Once diagnosed, hyperthyroidism can be treated with medication, radioactive iodine, or surgery, and your doctor may recommend lifestyle changes to help manage your symptoms.

Have you considered clinical trials for Hyperthyroidism?

We make it easy for you to participate in a clinical trial for Hyperthyroidism, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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