The thyroid is a small, butterfly-shaped gland located in the front of the neck, just below the Adam’s apple. Despite its small size, the thyroid plays a major role in regulating key body functions. It produces and releases hormones that help control your body’s metabolism, temperature, energy levels, growth, and development.

When the thyroid doesn’t function properly due to disease, growths, or other conditions, it can lead to a variety of symptoms that may significantly affect your health and daily life.

What Does the Thyroid Do?

The thyroid releases hormones into the bloodstream that regulate many critical processes in the body. The main hormones it produces include:

  • Triiodothyronine (T3)

  • Thyroxine (T4)

  • Calcitonin

T3 and T4 help control your body’s metabolism—the process by which your body converts food into energy. These hormones increase the energy needs of cells, which in turn influences your body temperature, heart rate, concentration, and how efficiently your body converts food to energy. In children, they also support growth and brain development.

Calcitonin helps regulate calcium levels in the body by influencing how calcium is used and stored.

Hormone production by the thyroid is tightly regulated by the pituitary gland, located at the base of the brain. This gland signals how much hormone the thyroid should release. If the thyroid produces too much or too little hormone, it can disrupt various bodily functions, including mood, digestion, and energy levels.

Common Signs of Thyroid Problems

The thyroid typically works behind the scenes, producing hormones at a steady pace. But when it produces too much or too little, you may start to notice changes in how your body feels and functions.

You might experience:

  • Weight gain or loss

  • Heat or cold intolerance

  • Excessive or reduced sweating

  • Menstrual changes

  • Muscle weakness

  • Constipation or diarrhea

  • Slow or rapid heart rate

  • Mood swings such as irritability, sadness, or anxiety

  • Swelling in the neck

  • Difficulty swallowing or breathing

Sometimes, the thyroid becomes enlarged or develops a growth (such as a nodule), which may be visible or noticeable to the touch.

Types of Thyroid Disorders

Several conditions can affect the thyroid, leading to imbalanced hormone levels. These include:

Hyperthyroidism

Hyperthyroidism occurs when the thyroid is overactive and produces too much hormone. This can speed up many body processes, leading to symptoms such as unexplained weight loss, increased sweating, rapid heartbeat, and nervousness.

The most common cause is Graves’ disease, an autoimmune condition in which the body attacks its own thyroid gland. Other causes include:

  • Thyroid nodules (typically non-cancerous growths)

  • Thyroiditis (inflammation of the thyroid)

  • Excessive iodine intake (from certain medications or supplements)

Hyperthyroidism is more common in women and people over 60. Risk increases with a family history of thyroid disease, recent childbirth, prior thyroid surgery, type 1 diabetes, or other autoimmune conditions.

Treatment may include medications, radioactive iodine therapy, or surgery to remove the thyroid.

Hypothyroidism

Hypothyroidism is the opposite—when the thyroid doesn’t produce enough hormone. This slows down the body’s functions, leading to symptoms such as fatigue, weight gain, depression, and hair thinning.

The most common cause is Hashimoto’s disease, another autoimmune disorder. Other causes include:

  • Thyroiditis

  • Surgical removal of the thyroid

  • Radiation treatments to the neck or thyroid

Hypothyroidism is also more common in women and older adults. Risk factors include family history of thyroid issues and autoimmune diseases such as Turner syndrome, Sjogren's syndrome, lupus, and rheumatoid arthritis.

Treatment typically involves daily thyroid hormone replacement therapy.

Thyroiditis

Thyroiditis refers to inflammation of the thyroid. It can lead to normal, elevated, or reduced thyroid hormone levels. Symptoms vary depending on the type and cause of the inflammation.

Thyroiditis caused by infections, trauma, or radiation is often painful and may cause neck tenderness. One of the most common forms is De Quervain’s thyroiditis, which is often linked to viral infections like flu or COVID-19.

Some types, like postpartum thyroiditis, cause no pain. It affects about 10% of women after childbirth. Because symptoms often resemble normal postpartum changes, it may go unnoticed.

In many cases, thyroiditis resolves on its own. Anti-inflammatory medications can ease discomfort, while hormone treatments may be needed if hormone levels become imbalanced.

Thyroid Nodules

Thyroid nodules are lumps or bumps that form in the thyroid gland. They can be solid or filled with fluid and are usually non-cancerous.

Most nodules don’t cause symptoms and are found incidentally during imaging tests. However, large nodules can cause difficulty swallowing or breathing and may become visible or palpable.

While nodules are more common with age, fewer than 10% are noticeable during a physical exam. Most are only detected through ultrasound. If a nodule is not growing or causing symptoms, it may not need immediate treatment—just regular monitoring.

Thyroid Cancer

Thyroid cancer occurs when thyroid cells grow uncontrollably. Most thyroid cancers develop from nodules, although only a small percentage of nodules are cancerous.

Symptoms may include a hoarse voice, neck swelling, or trouble swallowing or breathing—though most cancers don’t cause symptoms initially.

Thyroid cancer is more common in women, especially between the ages of 25 and 65. Risk factors include:

  • History of radiation therapy to the head or neck

  • Personal or family history of thyroid cancer

  • Having had a goiter

Treatment typically involves surgical removal of the thyroid, followed by radioactive iodine therapy if needed.

Goiter

A goiter is an enlarged thyroid gland. It can cause visible swelling in the neck and symptoms such as:

  • Throat tightness

  • Coughing

  • Swallowing or breathing difficulties

Goiters can result from iodine deficiency, thyroid nodules, thyroiditis, Graves’ disease, or Hashimoto’s disease. They are most common in women before menopause.

Diagnosing Thyroid Problems

To evaluate thyroid function, a healthcare provider may use several tools, including:

  • Medical history (including family history of thyroid disease)

  • Physical exam

  • Blood tests (T3, T4, TSH, thyroid antibodies)

  • Imaging tests (ultrasound, thyroid scan)

  • Radioactive iodine uptake test

  • Biopsy (to check if a growth is cancerous)

Typically, diagnosis begins with blood tests. Additional tests are ordered based on results and symptoms.

A Quick Review

The thyroid is a small gland with a big job. It produces hormones that regulate metabolism, growth, and energy levels. When the thyroid is not working properly—either underproducing or overproducing hormones—it can lead to a wide range of symptoms that affect your everyday life.

If you notice changes in your weight, mood, heart rate, energy levels, or experience swelling in your neck, it’s important to see a healthcare provider. With proper diagnosis and treatment, most thyroid conditions can be effectively managed.