Hypothyroidism can lead to anemia. This is because thyroid hormone, which is low in hypothyroidism, is important for red blood cell production and other metabolic functions.

Hypothyroidism is when your thyroid gland doesn’t make enough thyroid hormone. Researchers have estimated that hypothyroidism affects 11.7% of people in the United States.

Individuals with hypothyroidism are at a higher risk of experiencing anemia, a condition in which your blood has lower-than-normal levels of red blood cells.

Continue reading below to learn more about the connection between hypothyroidism and anemia, along with the symptoms and treatment of both conditions.

Hypothyroidism is linked with a higher risk of anemia. This association has been observed by doctors and scientists for well over a century.

A 2021 study using data from the U.K. Biobank found that participants who reported a diagnosis of hypothyroidism had higher odds of developing anemia.

This finding wasn’t associated with lifestyle choices or inflammation levels in the body. That means that other factors likely contribute to anemia in people with hypothyroidism.

In 2017, researchers reported that thyroid hormone is essential for the last steps of red blood cell production. Due to this, people with low thyroid hormone may not be able to make enough red blood cells, leading to anemia.

Other factors that may contribute to anemia in hypothyroidism include nutritional deficiencies, other coexisting conditions (comorbidities), and the effects of hypothyroidism on the bone marrow (where red blood cells are made).

Some older research found that anemia was only more likely in people with overt hypothyroidism, where thyroid hormone levels are lower than usual, and symptoms were present.

However, a more recent study suggested that anemia also occurs in subclinical hypothyroidism, in which thyroid hormone levels are mildly decreased. People with subclinical hypothyroidism may not have obvious symptoms.

Research has also found that some people with thyroid conditions may have low vitamin B12 or iron, which can lead to certain forms of anemia.

This occurs because autoimmune diseases can cluster. Those with Hashimoto’s thyroiditis, for example, have an increased risk of pernicious anemia or celiac disease, both of which can result in anemia.

Hypothyroidism has also been associated with heavy periods. And heavy or prolonged bleeding during menstruation can lead to iron deficiency and anemia.

Researchers believe menstrual irregularities from hypothyroidism are due to two things:

Does anemia cause hypothyroidism?

It’s also possible that having anemia can affect the function of your thyroid gland, but this is rare. One 2019 case study described hypothyroidism occurring due to severe iron-deficiency anemia.

Iron-deficiency anemia is the most common type of anemia and happens when you don’t have enough iron in your body.

Iron is an important component of one of the enzymes involved in making thyroid hormone. This means that low iron levels can impair thyroid hormone production.

A 2023 meta-analysis found a link between iron deficiency and thyroid dysfunction.

This section reviews symptoms of hypothyroidism and anemia.

Hypothyroidism symptoms

While the symptoms of hypothyroidism may vary by individual, some of the most common ones include:

Anemia symptoms

If you have anemia, you may experience symptoms like:

See a doctor if you’re experiencing any of the above symptoms.

The exact treatment for anemia depends on what’s causing it. Generally speaking, anemia treatments can include one or a combination of medications, dietary supplements, and lifestyle changes.

Hypothyroidism is treated using a medication called levothyroxine. Taking levothyroxine helps replace the thyroid hormone that your thyroid gland isn’t making.

If hypothyroidism is contributing to your anemia, managing your thyroid hormone levels with levothyroxine may help treat it.

If other nutritional deficiencies, such as a deficiency in iron, are also present, your doctor may also recommend appropriate supplements.

If you’re taking levothyroxine, doctors commonly recommend that you take your iron supplement at least 4 hours before or after your levothyroxine. This is because iron supplements can interfere with levothyroxine absorption, making it less effective.

However, be sure to talk with your doctor about the timing of your levothyroxine and iron supplements. They can provide recommendations based on your individual health.

If you have hypothyroidism and anemia, addressing your thyroid hormone levels with levothyroxine or managing iron deficiency with supplements should help to ease your anemia.

A 2025 study of people with thyroid dysfunction and anemia found that managing thyroid hormone levels improved hemoglobin (a protein in red blood cells that carries oxygen).

Hemoglobin is a marker that’s measured during anemia diagnosis.

Even if your hypothyroidism is treated, it’s still possible to get anemia again in the future. That’s because there are many other causes of anemia, including nutritional deficiencies, other health conditions, and blood loss.

People with hypothyroidism are more likely to experience anemia. This is likely due to the role that thyroid hormone plays in the production of red blood cells.

Anemia due to hypothyroidism can typically be treated by raising thyroid hormone levels using levothyroxine. Nutritional supplements may be recommended if deficiencies are present.

Make an appointment with a doctor if you have symptoms of hypothyroidism, anemia, or both. They can do tests to find out what’s causing your symptoms and develop an appropriate treatment plan.