What is hypothyroidism?

Hypothyroidism is the most common type of thyroid disorder. It means your thyroid gland is not active enough. This tiny gland is found in the front of your neck. Its job is to make thyroid hormone. If the gland is underactive, it may not make enough thyroid hormone.

Thyroid hormones control how your body uses energy. They affect almost every organ in your body. When your thyroid doesn’t make enough of these hormones, parts of your body slow down.  

What causes hypothyroidism?

The most common cause of hypothyroidism is an autoimmune disorder. This means your immune system starts to attack itself. It makes antibodies against the thyroid gland. Another cause may be treatment for an overactive thyroid gland. That may include radioactive iodine therapy or surgery.

A condition called secondary hypothyroidism can also sometimes happen. It’s when your pituitary gland stops working. The pituitary gland then no longer tells the thyroid gland to make thyroid hormones.

Newborns are tested at birth for hypothyroidism. This condition must be treated immediately. It can affect a baby’s brain and nervous system.

Who is at risk for hypothyroidism?

You may be more likely to have hypothyroidism if you:

  • Are a woman
  • Are older than age 60
  • Have had thyroid problems or thyroid surgery in the past
  • Have a family history of thyroid problems
  • Have certain conditions, such as type 1 diabetes or rheumatoid arthritis
  • Have Turner syndrome, a genetic condition that affects women
  • Are pregnant or have had a baby within the past 6 months
  • Have an iodine deficiency. Your body needs iodine to make thyroid hormone.

What are the symptoms of hypothyroidism?

Symptoms are different for each person. They are usually hard to notice and start slowly. They may be mistaken for symptoms of depression. Here are the most common symptoms and signs:

  • Dull facial expressions
  • Tiredness (fatigue)
  • Being cold bothers you
  • Hoarse voice
  • Slow speech
  • Droopy eyelids
  • Puffy and swollen face
  • Weight gain
  • Constipation
  • Sparse, coarse, and dry hair
  • Coarse, dry, and thickened skin
  • Hand tingling or pain (carpal tunnel syndrome)
  • Slow pulse
  • Muscle cramps
  • Sides of eyebrows thin or fall out
  • Confusion
  • Increased or irregular menstrual flow in women

These symptoms may look like other health problems. Always see your healthcare provider for a diagnosis.

How is hypothyroidism diagnosed?

Your healthcare provider will ask about your past health. You will also need an exam. Blood tests can also help diagnose hypothyroidism. They can measure the amount of thyroid hormone and thyroid-stimulating hormones in your blood.

How is hypothyroidism treated?

Your healthcare provider will figure out the best treatment for you based on:

  • Your age, overall health, and past health
  • How sick you are
  • How well you can handle certain medicines, treatments, or therapies
  • How long the condition is expected to last
  • Your opinion or preference
The goal of treatment is to return your level of thyroid hormone back to normal. You may need to take medicine that gives you a dose of thyroid hormones. Your provider may need to change the dose over time. You will need blood tests to make sure you are taking the correct dose of thyroid hormone replacement. You will probably need to take this medicine for the rest of your life.

What are the complications of hypothyroidism?

If your hypothyroidism is not treated, these complications may happen:

  • Anemia
  • Low body temperature
  • Heart failure

When should I call my healthcare provider?

Tell your healthcare provider if your symptoms get worse or you have new symptoms. If you are a woman of childbearing age and want to become pregnant, talk with your healthcare provider first.

Key points about hypothyroidism

  • Hypothyroidism means your thyroid gland is underactive. It isn’t making enough thyroid hormone. The most common cause is when your immune system starts to attack itself. It makes antibodies against the thyroid gland.
  • Symptoms include dull facial expressions, tiredness, and weight gain.
  • Blood tests can help diagnose this condition. They can measure the amount of thyroid hormone and thyroid-stimulating hormones in your blood.
  • The goal of treatment is to return your levels of thyroid hormone back to normal.
  • Untreated hypothyroidism may lead to anemia, low body temperature, and heart failure.
  • Treatment may include medicine that replaces lost thyroid hormones. You usually will need to take thyroid hormones for the rest of your life.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

Seminar Webinar: Thyroid Disease, an Often Surprising Diagnosis

doctor examining patient's neck

Join endocrinologist Paul Ladenson, M.D., as he outlines the signs and symptoms of the various thyroid disorders and discusses the interplay among other diseases and the thyroid. The webinar recording is presented as part of A Woman’s Journey Conversations That Matter webinar series.

Request an Appointment

Find a Doctor
Find a Doctor