Hyperthyroidism is a condition in which the thyroid gland produces too many hormones. Because thyroid hormones regulate metabolism, elevated levels can cause symptoms like anxiety and weight loss. If left untreated, hyperthyroidism can increase the risk of more serious health issues.
While hyperthyroidism can be challenging to live with, the good news is that most people respond well to treatment and can manage their symptoms effectively.
Here, we’ll explore what hyperthyroidism is, including its symptoms, causes, and treatment options, plus ways to support thyroid health.
What is hyperthyroidism?
Hyperthyroidism, also known as overactive thyroid, occurs when the thyroid gland produces too much thyroxine and triiodothyronine – the body’s main thyroid hormones.
Because thyroid hormones regulate metabolism, elevated levels can cause a range of symptoms, including anxiety, nervousness, hyperactivity, and unplanned or unexplained weight loss.
What are the symptoms of hyperthyroidism?
According to the NHS, symptoms of hyperthyroidism can vary in nature, severity, and frequency. Most people experience only some of these symptoms, not all of them.
Symptoms of hyperthyroidism can include…
- Mood swings, including anxiety, irritability, and nervousness
- Struggling to sleep (insomnia) and feeling tired all the time
- Neck swelling caused by an enlarged thyroid gland
- Shaking or trembling
- Hyperactivity
- Weak muscles
- Patchy hair loss (alopecia)
- Sensitivity to heat or excessive sweating
- Unexplained or unexpected weight loss, even if you’re eating more
- Loss of interest in sex
- Needing to use the toilet more frequently
Head over to the NHS website to read more about hyperthyroidism symptoms.
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What can cause hyperthyroidism, and are there any risk factors?
While hyperthyroidism can affect anyone, it’s around 10 times more common in women than men and typically occurs between the ages of 20 and 40.
We’ll explore some of the main causes below.
Graves’ disease
Graves’ disease is an autoimmune condition that causes the immune system to mistakenly attack the thyroid gland, leading to an overproduction of thyroid hormones.
According to NICE, Graves’ disease is the most common cause of an overactive thyroid, responsible for around 80% of cases. Women, people who smoke, and those with a family history of autoimmune conditions, such as type 1 diabetes, carry the highest risk. Graves’ disease usually develops between the ages of 30 and 50.
Graves’ ophthalmopathy is a complication of Graves’ disease that can cause symptoms like eye discomfort, double vision, and bulging eyes. The NHS has more information about Graves’ ophthalmopathy and other complications of hyperthyroidism on their website.
Thyroid nodules
According to NICE, the second most common cause of hyperthyroidism in the UK is thyroid nodules (mostly non-cancerous lumps that develop in the thyroid gland).
Some nodules contain abnormal thyroid tissue, causing them to produce thyroid hormones independently, ignoring the body’s signals to slow down production and raising levels above the normal range. Nodules containing abnormal thyroid tissue, referred to as ‘toxic thyroid nodules’, account for around one in 20 cases of hyperthyroidism.
Experts are currently unsure why thyroid nodules develop, but people over 60 and those living in iodine-deficient areas are thought to have a higher risk.
Iodine supplements
Iodine is an essential mineral that the body needs to function. It’s involved in metabolism, thyroid health, and immunity, among other things. When it comes to thyroid health specifically, the thyroid gland uses iodine to produce thyroid hormones.
As a result, taking iodine supplements can sometimes cause overproduction of thyroid hormones. This is known as iodine-induced hyperthyroidism, also called Jod-Basedow phenomenon.
However, according to the NHS, iodine-induced hyperthyroidism mainly occurs in people with pre-existing thyroid issues.
Certain medications
Amiodarone is a type of medication used to help control an irregular heartbeat (atrial fibrillation).
Because it contains iodine, amiodarone can sometimes lead to hyperthyroidism if you are already struggling with thyroid issues.
Follicular thyroid cancer
Hyperthyroidism can sometimes be caused by thyroid cancer that starts in thyroid follicles and begins to produce thyroid hormones. However, according to the NHS, this is rare.
How is hyperthyroidism diagnosed?
If you suspect you may have hyperthyroidism, it’s important to speak to your GP so that you can access any support and treatment you may need. After hearing about your symptoms, your GP may arrange blood tests to check how well your thyroid gland is working. These are known as thyroid function tests.
If your thyroid hormone levels are high, you may be referred to a specialist for further tests to determine the underlying cause. This may include additional blood tests or an isotope thyroid scan, which involves swallowing small amounts of a radioactive substance (an isotope) in capsule or liquid form and seeing how much your thyroid gland absorbs.
According to the NHS, high absorption rates are likely to indicate Graves’ disease or thyroid nodules, while low absorption may be the result of swelling in the thyroid gland, too much iodine, and, in rare cases, thyroid cancer.
You can read more about diagnosing hyperthyroidism on the NHS website.
How is hyperthyroidism treated?
According to NICE guidelines, if you’re diagnosed with hyperthyroidism, your GP should refer you to a hormone condition specialist (endocrinologist) to plan your treatment.
The three main treatments for hyperthyroidism are medicine, radioactive iodine treatment, and surgery, which we’ll cover below.
To read more about the suitability and potential side effects of each treatment, head over to the NHS website.
Medicine
Medicines called thionamides are a common treatment for hyperthyroidism. They work by stopping your thyroid gland from producing excess hormones.
The main types of thionamides, carbimazole and propylthiouracil, are usually taken for 12-18 months.
It’s important to note that, because thionamides work by affecting hormone production rather than reducing current levels, it can take several weeks before you notice improvements.
As a result, some people are temporarily prescribed beta blockers alongside thionamides to help temporarily relieve symptoms like shaking, trembling, hyperactivity, and a rapid heartbeat.
Once thyroid hormone levels are under control, your specialist may gradually reduce your dose, eventually stopping entirely. However, some people may need to continue taking medicine for several years, or even life.
Radioactive iodine treatment
Radioactive iodine treatment is a type of radiotherapy that destroys cells in the thyroid gland, reducing the amount of hormones it can produce.
It’s given as either a drink or capsule and contains iodine and a low dose of radiation, which is absorbed by the thyroid gland. Radioactive iodine is a highly effective treatment and, while it can take a few weeks or months to see results, most people need only a single dose.
Although the dose of radiation used during radioactive iodine treatment is very low, you’ll still need to take some precautions after treatment, such as avoiding prolonged close contact with children and pregnant women
Deciding between medicine and radioactive iodine treatment
Depending on factors like age, symptoms, and hormone levels, you may be offered a choice between thionamides or radioiodine treatment. Both treatments have advantages and disadvantages, and the right one for you will depend on several factors, including personal preference.
For example, while thionamides may not be as successful as radioactive iodine treatment, they’re more straightforward and don’t have to be administered in a hospital. Similarly, thionamides carry a higher risk of side effects, but radioiodine treatment isn’t usually suitable for people with complications like Graves’ ophthalmopathy.
You can read more about the pros and cons of thionamides and radioiodine on the NHS website.
Surgery
In some cases, surgery may be recommended to remove all or part of the thyroid gland. This may be recommended if your thyroid gland is severely swollen and causing neck problems, or if you’re unable to have other, less invasive treatments.
Surgery to remove the thyroid gland is a permanent cure for hyperthyroidism, so it may also be recommended if symptoms return after trying other treatments.
However, it’s important to note that, because removing your thyroid means your body will be unable to produce thyroid hormones, you’ll need to take hormone replacement medicine for the rest of your life.
3 natural ways to support thyroid health
If you’ve been diagnosed with a thyroid condition, it’s natural to want to look for ways to reduce your symptoms, support your thyroid health, and boost the effectiveness of prescribed medication.
Below, we’ll take a closer look at some natural ways to help support thyroid health.
Note: It’s important to speak to your GP before introducing anything to complement hyperthyroidism treatment, including supplements.
1. Consider your diet
When it comes to supporting health, diet is often a main area of focus. However, it’s important to note that while many websites offer advice on what to eat and avoid, there’s currently no official ‘thyroid diet’.
Generally speaking, experts say the most important thing you can do for thyroid health is to eat a varied, balanced diet low in ultra-processed foods. While it’s true that certain nutrients, like iodine and selenium, are more involved in thyroid health, there’s currently insufficient evidence to support using them as treatment. In fact, NICE guidelines do not recommend iodine or selenium supplements for managing hyperthyroidism, unless a deficiency is identified.
For example, due to the role of iodine in thyroid hormone production, you may have heard of low-iodine diets. However, according to the British Thyroid Foundation, low-iodine diets are usually only advised for those undergoing radioactive iodine treatment (RAI) for thyroid cancer. Meanwhile, those undergoing RAI for hyperthyroidism aren’t required to reduce their iodine intake unless advised by their GP or medical team.
More generally, simple steps like reducing caffeine intake, which is linked with anxiety, insomnia, tremors, and palpitations, may be helpful. You can read more about diet and supplement advice for thyroid conditions on the British Thyroid Foundation website.
2. Take steps to manage stress
Many people with hyperthyroidism experience psychological symptoms like anxiety and mood swings. So, taking steps to regulate your emotions and manage stress can be beneficial.
Chronic stress, in particular, has been found to negatively affect various bodily functions, including the production of thyroid hormones.
Things like prioritising good quality sleep, limiting screen time, and taking time for yourself can also be useful steps to take. Check out our article, 7 tips for coping with stress and anxiety, for more ideas.
3. Maintain a regular exercise routine
Exercise is beneficial for thyroid health because, among other things, it can help to reduce excess body fat, which is linked with a greater risk of inflammation and insulin resistance – two factors that can affect thyroid health.
If you’re yet to find a form of exercise that you enjoy, head over to our fitness and exercise section. Alternatively, you might like to join a Rest Less Events fitness class.
Worried about accessing the NHS care you need?
83% of Rest Less members are worried about accessing the healthcare they need on the NHS#, making fast access to treatment more important than ever.
HMCA private medical cover offers affordable, flexible plans, with 90% of members saving money when they switch. Enjoy peace of mind. Join today and get £150 off your subscription.
#Data from over 1,000 Rest Less members surveyed in 2025
^Data from HMCA members who joined between 01/01/25 and 30/06/25
I’m struggling with hyperthyroidism – where can I turn for support?
If hyperthyroidism is impacting your daily life, it’s important to remember that you’re not alone. There are various resources available to help and support you.
Thyroid UK provides information and support for people with thyroid disorders in the UK – including online webinars and community events where you can connect with others going through similar experiences.
Similarly, the British Thyroid Foundation offers a telephone helpline, patient forums, and access to valuable research into living better with thyroid conditions.
Final thoughts…
Due to the role of the thyroid in metabolism, thyroid conditions like hyperthyroidism can impact everything from mood to weight management. While hyperthyroidism can be difficult to live with, the good news is that, with the right treatment, most people can enjoy healthy, happy lives.
For further reading, head over to our health section. Here, you’ll find information on everything from bone and heart health to important health checks for over 50s.
Do you have any experience with hyperthyroidism that you’d like to share? We’d be interested to hear from you in the comments below.
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