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Quick Facts



The Manual's Editorial Staff

Last full review/revision Jul 2020| Content last modified Jul 2020
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Your thyroid is a gland below the Adam’s apple in your neck.

Your thyroid releases thyroid hormones. The hormones control how fast your body’s chemical functions work (metabolic rate). Almost every cell in your body needs thyroid hormones. Among many other things, thyroid hormones help control:

  • How fast you burn calories

  • How fast your heart beats

  • Your body temperature

Iodine is needed by your thyroid gland in order to make thyroid hormones. You need only a tiny amount of iodine. But if your thyroid gland doesn't get iodine, it won't make enough thyroid hormones.

Locating the Thyroid Gland

Locating the Thyroid Gland

What is hypothyroidism?

Hypothyroidism is when your thyroid doesn't make enough thyroid hormones.

What causes hypothyroidism?

Causes of hypothyroidism include:

Lack of iodine is rare in modern countries. Most countries put a little iodine in salt so everybody gets enough. There's also iodine in seafood. People in some poor countries far from the sea are at risk of not getting enough iodine.

The pituitary gland Overview of the Pituitary Gland The pituitary gland is a pea-sized bit of tissue at the bottom of your brain. Glands are organs that make and release hormones into your blood. Hormones are chemicals that stimulate other cells... read more in your brain makes a hormone called TSH that tells your thyroid to make thyroid hormones. If you have a problem with your pituitary gland, it might not make TSH and you'll get hypothyroidism.

Who can get hypothyroidism?

Almost anyone can get hypothyroidism, but it's more common in older people. Sometimes, hypothyroidism can happen in:

What are the symptoms of hypothyroidism?

Not enough thyroid hormones cause your body functions to slow down, which can affect how you look, sound, or feel.

Symptoms that affect the way you look or sound may include:

  • Puffy eyes and face and droopy eyelids

  • Thin, rough, dry hair

  • Rough, dry, scaly, thick skin

  • Hoarse voice and slow speech

Symptoms that affect the way you feel may include:

If not treated, hypothyroidism can eventually cause:

How can doctors tell if I have hypothyroidism?

How do doctors treat hypothyroidism?

Doctors treat hypothyroidism with:

  • Thyroid hormone pills

After you start the pills, your doctor will gradually adjust the dose based on your TSH level. It's important to talk to your doctor about medicines that interfere with absorbing thyroid hormone. Such medicines include iron, calcium, and some antacids.

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