Thyroid Conditions

What Is the Thyroid Gland?

Julie Lynn Marks
By Medically Reviewed by 
Reviewed:
Medically Reviewed

This gland helps control your metabolism and other important bodily functions.

The thyroid gland is a butterfly-shaped organ about two inches long. It’s located near the base of your neck right above your collarbone.

It releases hormones that help control your metabolism and other important processes in the body.

Noticeable thyroid cartilage is sometimes referred to as an Adam's apple.

The thyroid gland is part of the endocrine system, which is made up of organs that produce, store, and release hormones into the bloodstream.

Thyroid Gland Function

The thyroid gland makes the hormones thyroxine (T4) and triiodothyronine (T3), which affect your metabolism (how your body uses energy) and almost every other organ in your body.

The thyroid gland constantly releases hormones into the bloodstream.

It produces more of the hormones when your body needs more energy, and less of them when your body needs less energy.

Thyroid hormones also play a role in regulating:

  • Heart rate
  • Breathing
  • Brain development
  • Muscle strength
  • Body temperature
  • Menstrual cycles
  • Cholesterol levels
  • Body weight
  • Nervous system function

Thyroid Disorders

About 20 million Americans have some type of thyroid disorder, according to the American Thyroid Association.

The most common disorders are:

Hypothyroidism (underactive thyroid): This occurs when your body doesn’t make enough thyroid hormones.

Symptoms of hypothyroidism include weight gain, tiredness, feeling cold, depression, dry skin, heavy menstrual periods, trouble sleeping, thinning hair, and poor concentration.

Hyperthyroidism (overactive thyroid): This occurs when your body overproduces thyroid hormones.

Symptoms of hyperthyroidism include weight loss, anxiety, nervousness, tremor, sensitivity to heat, hot flashes, hair loss, and sore eyes.

Other thyroid disorders include

  • Post-partum thyroiditis (hormone irregularities after having a baby)
  • Thyroid nodules (lumps that are usually benign (harmless) that in some cases may stop the thyroid from working properly)
  • Thyroid eye disease (an eye problem that affects some people with the autoimmune disorder Graves' disease).

Your doctor may check for thyroid disorders by performing a physical exam, ordering a blood test, or using an imaging scan.

Most thyroid disorders can be treated with oral medications.

Thyroid Cancer

Thyroid cancer is cancer that begins in the thyroid gland.

There are about 62,000 new cases of thyroid cancer in the United States each year, according to the American Cancer Society.

The first sign of thyroid cancer is usually a nodule (lump) in the thyroid gland. However, less than 1 percent of all thyroid lumps are cancerous.

Thyroid Goiter

A goiter is an enlargement of the thyroid gland.

It sometimes occurs in people with a thyroid gland that under- or overproduces hormones.

A goiter can also affect people with a normally functioning thyroid gland.

Goiters are typically painless, but a large one can make swallowing or breathing difficult.

Worldwide, the most common cause of goiters is a lack of iodine in the diet.

In the United States, the condition is more often caused by an under- or overactive thyroid gland.

Some people with goiters don't require treatment. Others may need medications or surgery.

Thyroid Hair Loss

Hair loss can be caused by many things, such as medications or hormone changes, and it’s a common side effect of thyroid disorders.

Overproduction of thyroid hormones can cause fine, thinning hair. Underproduction of thyroid hormones can lead to loss of hair on the scalp and body.

Proper treatment for your thyroid disorder will usually stop any hair loss.

Thyroid Weight Gain

Weight gain can be caused by many factors, and is commonly due to more calories consumed than burned, even in people with an underactive thyroid.

Hypothyroid people can experience weight gain and have difficulty losing extra weight, despite adopting healthy habits.

Most of the time, an excess of salt and water in the body is the cause.

Proper treatment can bring your thyroid hormone levels to normal, which may help you lose the extra weight.

Thyroid Problems in Women

Women are more likely to have thyroid disorders than men.

In fact, one in eight women will develop a thyroid problem at some point, according to the Office on Women's Health.

In women, thyroid disorders can cause problems and irregularities with menstrual periods. They can also affect your ability to get pregnant and have a healthy baby.

Symptoms of thyroid problems are often mistaken as menopause in women.

Thyroid Problems in Men

Although thyroid problems are more likely to affect women, men can also develop them.

In fact, thyroid disorders are thought to be underdiagnosed in men.

Men suffer from many of the same symptoms as women, but may also experience:

If you think you may have a thyroid problem, be sure to find a doctor who's experienced in treating and diagnosing men with thyroid disorders.

Learn More About TSH (Thyroid-Stimulating Hormone)

Learn More About Goiter

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