What to know about an overactive thyroid gland

An overactive thyroid gland — also known as hyperthyroidism or thyrotoxicosis — occurs when the thyroid produces too much hormone. This can cause symptoms such as weight loss, anxiety, tremor, sweating, heat intolerance, and a fast or irregular heartbeat.

As a thyroid specialist in London, I regularly see patients with these symptoms who are concerned about their thyroid health. The good news is that hyperthyroidism is a very treatable condition, but successful management depends on accurately identifying the underlying cause.

The different causes of an overactive thyroid

There are several possible reasons why the thyroid gland becomes overactive. Understanding which applies to you is essential for selecting the most effective treatment.

• Graves’ disease – An autoimmune thyroid disorder where the immune system causes the thyroid to produce too much hormone. This can also be linked to thyroid eye disease, which causes eye irritation, swelling, or discomfort. Graves’ disease is one of the most common causes of an overactive thyroid.
• Thyroiditis – Inflammation of the thyroid gland can cause a temporary (transient) period of overactivity. It often resolves naturally as the gland recovers.
• Overactive thyroid nodule – Sometimes a single nodule in the thyroid produces excess hormone independently of the rest of the gland.

·        Multinodular goitre – When the thyroid contains multiple nodules, these can collectively produce too much hormone.

• Thyroid function tests around pregnancy – Some women experience a temporary flare of thyroid overactivity after giving birth, which needs to be differentiated from other causes of hyperthyroidism.

Diagnosing an overactive thyroid

Accurate diagnosis is the foundation of effective treatment. At The London Lauriston Clinic, we take a careful and structured approach, which includes:

• Comprehensive medical history and examination – with assessment of the neck and thyroid gland.
• Thyroid function tests – to measure hormone levels (T3, T4) and thyroid-stimulating hormone (TSH).
• Thyroid antibody testing – to detect autoimmune causes such as Graves’ disease.
• Ultrasound scan of the thyroid – to evaluate the gland’s structure and identify nodules.
• Thyroid uptake scans (when appropriate) – to show which parts of the thyroid are overactive.

This thorough assessment allows us to pinpoint the exact cause and tailor treatment accordingly.

Treatment options

Treatment depends on the underlying cause, your medical history, and personal preferences. Common options include:

• Medication – Antithyroid drugs are used to reduce hormone production and restore balance. We also sometimes prescribe medications to reduce the effects of excess thyroid hormone, such as those that help slow a fast heart rate or reduce tremor, while treating the underlying condition.
• Radioactive iodine therapy – A targeted, safe treatment that gently reduces thyroid activity.
• Surgery – In selected cases, part or all of the thyroid gland may be removed.

At The London Lauriston Clinic, we work within a multidisciplinary team, including endocrinologists, thyroid surgeons, radiologists, and other specialists. This ensures each patient receives personalised, evidence-based care.

We focus on shared decision-making, taking time to discuss all options so that patients can make informed choices and feel confident about their treatment plan.

When to see a thyroid specialist

You should seek medical advice if you notice:

• Unexplained weight loss or anxiety
• Tremor, sweating, or heat intolerance
• A fast or irregular heartbeat
• Neck swelling or a thyroid lump
• Thyroid-related symptoms during or after pregnancy

Early assessment by an experienced thyroid endocrinologist in London can help restore thyroid balance, improve wellbeing, and prevent complications.

At The London Lauriston Clinic, we offer expert, multidisciplinary care for all thyroid conditions — including overactive thyroid, Graves’ disease, thyroid nodules, and pregnancy-related thyroid changes.

Dr Srirangalingam is a consultant endocrinologist in London specialising in thyroid, pituitary, and adrenal disorders. He sees private patients at The London Lauriston Clinic, providing expert, individualised care for all aspects of thyroid health.