Tired or anxious? It could be thyroid disease.

January 25, 2024 Providence Health Team


In this article:

  • Some of the most common symptoms of thyroid disease include fatigue, cold or heat intolerance, anxiety and heart palpitations.

  • The best way to diagnose thyroid disease is through a simple blood test to detect levels of thyroid hormones.

  • Treatment for hyperthyroidism can range from medication to surgery, while treatment for hypothyroidism usually involves the medication levothyroxine.

 For a gland that’s only about the size of your thumb, the thyroid gland is certainly important in the body. Its main job is to control how the body uses energy by producing and releasing certain hormones.

When your thyroid function isn’t working right, it can cause major havoc in your body. So how do you know when that’s happening? “If you're experiencing symptoms such as unexplained fatigue, heat or cold intolerance, anxiety, heart palpitations, hair loss or tremors, talk to your doctor about testing for thyroid disease,” said Chih-Han Lee, M.D., an endocrinologist at Providence’s Facey Medical Group in Burbank, California. “Because symptoms of thyroid disease are often nonspecific, clinicians rely on blood tests to make the diagnosis.”

January is Thyroid Awareness Month, so let’s take a look at some basic facts about thyroid disease.

What are the types of thyroid disease?

Thyroid disease is a general term for a condition that keeps your body from making the right amount of hormones. There are two main types of thyroid disease: hypothyroidism and hyperthyroidism.


Hypothyroidism, or an underactive thyroid, is when your body doesn’t make enough thyroid hormones. This condition can lower your basal metabolic rate (BMR), which is how many calories you burn when you’re at rest. There are several different conditions that are causes of hypothyroidism, including:

  • Thyroiditis, when your thyroid gland swells and lowers the amount of hormones your thyroid produces.
  • Hashimoto’s disease, an autoimmune disorder in which the body’s cells attack and damage the thyroid.
  • Not enough iodine, which is used by the thyroid to produce hormones.
  • A thyroid gland that doesn’t work, a condition that occurs in about 1 in 4,000 newborns.
  • Postpartum thyroiditis, a condition that occurs in 5-9% of women after childbirth and is usually temporary. 


Hyperthyroidism, or an overactive thyroid, is when your body makes more thyroid hormone than it needs. This can increase your basic metabolic rate (BMR) and possibly make it harder to gain weight. Some of the most common causes of hyperthyroidism include:

  • Graves’ disease, which causes the entire thyroid gland to be overactive and produce too much thyroid hormone.
  • Thyroiditis, in which the thyroid releases hormones that were stored there.
  • Overactive nodules within the thyroid.
  • Excessive iodine in the body, which causes it to make more thyroid hormones than it needs.

“Thyroid diseases are quite common,” said Dr. Lee. “It has been estimated that more than 12% of the U.S. population will develop a thyroid condition during their lifetime, so it's definitely worth checking into.”

Signs and symptoms of hypo- and hyperthyroidism

Hypothyroidism may not cause many symptoms in the early stages, but over time, it can lead to:

  • Depression
  • Fatigue
  • Heavier than normal or irregular menstrual periods
  • Increased sensitivity to cold
  • Memory problems
  • Muscle aches
  • Slowed heart rate
  • Weight gain

Symptoms of hyperthyroidism can include a few of the opposite effects:

  • Nervousness and irritability
  • Sudden, unexplained weight loss
  • Hyperactivity
  • Muscle weakness
  • Itchiness
  • Mood swings
  • Sensitivity to heat

Generally, the best way to diagnose thyroid disease is through a blood test, which detects your thyroid hormone levels. If those levels are abnormal, you may need to undergo treatment for thyroid disease.

Treatment for thyroid disease

In treatment, your doctor ultimately wants to return your thyroid hormone levels to normal, which may involve either increasing or decreasing them.

For hyperthyroidism, treatment can include:

  • Anti-thyroid medications, which stop your thyroid from making hormones.
  • Beta blocker medications that help you manage your symptoms.
  • Radioactive iodine that prevents your thyroid from making high levels of the hormones.
  • Surgical removal of the thyroid, which is only considered when other treatments have failed.

Treatment for hypothyroidism is much simpler: Your doctor will likely prescribe the thyroid hormone medicine levothyroxine, which you will need to take every day.

How does iodine relate to thyroid disease?

The only known function of iodine in the body is to help the thyroid gland make T3 and T4 hormones. And since the body doesn’t produce iodine, it must come from your diet. If you don’t eat enough iodine, you usually don’t make enough thyroid hormone. This can lead to a thyroid condition, such as hypothyroidism.

In the U.S., you usually don’t have to worry about not getting enough iodine — foods like iodized salt, dairy products and even multivitamins help you get enough from a balanced diet. Iodine deficiency can be a problem in other areas of the world, though.

More iodine isn’t always the answer. Some studies have found that not getting enough iodine or getting too much iodine is linked to a higher risk of having a thyroid disorder. Too much iodine can also mess with thyroid hormone levels, especially for people who already have a thyroid condition.

If you eat a balanced diet, you should be getting an appropriate amount of iodine. Your provider can usually check your iodine levels with a urine or blood test.

The most important step in dealing with thyroid dysfunction is being honest with your health care provider about your symptoms. “It’s not something that we routinely check for, so we rely on our patients to tell us how they are feeling,” said Dr. Lee. 

Contributing caregiver

Chih-Han Lee, M.D., an endocrinologist at Providence’s Facey Medical Group in Burbank, California

Find a doctor

If you think you might have a thyroid condition, our endocrinology experts can help. You can find a provider using our provider directory.

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Related resources

The ins and outs of Hashimoto’s disease

What women need to know about hormones and mental health

New treatment for thyroid cancer

This information is not intended as a substitute for professional medical care. Always follow your health care professional’s instructions.

About the Author

The Providence Health Team brings together caregivers from diverse backgrounds to bring you clinically-sound, data-driven advice to help you live your happiest and healthiest selves.

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