Research shows that there may be a link between these two health conditions. But the nature of the possible link remains unclear.

The thyroid is a butterfly-shaped gland that produces hormones involved in regulating the body’s metabolism. A doctor diagnoses hypothyroidism when the thyroid does not produce enough of these hormones. It can cause a range of symptoms, including weight gain, depression, and fatigue.

Migraine is a neurological condition. It can cause sensory disturbances, and moderate to severe headaches, among other symptoms. The pain may only affect one side of the head.

Research suggests a possible link between hypothyroidism and migraine. This article explores the potential connection, including whether migraine may be a risk factor for hypothyroidism. It also describes the treatment for hypothyroidism and when to see a doctor.

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Experts do not yet understand whether hypothyroidism might cause migraine, or whether migraine could be a risk factor for hypothyroidism.

According to the International Headache Society (IHS), approximately 30% of people with hypothyroidism have a history of migraine. People with hypothyroidism may also have headaches, including pulsing pain, on both sides of the head. In most cases, the headaches subside after the person receives effective treatment for hypothyroidism.

The IHS classifies headaches attributed to hypothyroidism. According to this system of classification, a person may have a headache attributed to hypothyroidism if they have:

  • a diagnosis of hypothyroidism
  • pain on both sides of the head that usually subsides after successful hypothyroidism treatment
  • evidence that the hypothyroidism may have caused the migraine, which must include at least two of these criteria:
    1. the headache developed before the hypothyroidism or may have led to its discovery
    2. either or both of the following:
      • significant, simultaneous worsening of the headaches and hypothyroidism
      • significant improvement or resolution of the headaches following improvement or resolution of the hypothyroidism
    3. the headache has either or both of these characteristics:
      • it occurs on both sides
      • it is constant

A doctor may use these criteria to diagnose a headache linked with hypothyroidism if these criteria best fit the person’s symptoms, and no other diagnosis seems more likely.

Overall, as a 2019 review observes, there appears to be a link between hypothyroidism and migraine, but researchers have yet to discover what that would explain this link.

Hypothyroidism is 8–9 times more common in women than men. Also, the risk of developing a thyroid issue increases for people who have recently given birth. A thyroid condition called postpartum thyroiditis affects almost 10% of women and presents around 8–20 weeks after delivery.

Experts do not fully understand why the risk of a thyroid condition is higher for women. It may be because women are two times more likely to develop an autoimmune disorder, compared with men.

Most cases of hypothyroidism stem from an autoimmune disease, in which the immune system mistakenly attacks thyroid cells. These diseases can occur due to very significant fluctuations in hormones, such as during pregnancy or menopause.

Migraine is also more common among women than men. According to the National Institute for Health and Care Excellence, around 33% of women experience migraine at some point, compared with 13% of men. Prior to puberty, however, this rate is equal. The difference in prevalence after puberty suggests that hormonal factors may be involved.

This is possible, but it is still unclear whether one health issue increases the risk of developing the other.

A 2016 study found that around 7% of participants with a preexisting headache disorder went on to receive a diagnosis of new-onset hypothyroidism.

Meanwhile, having hypothyroidism may increase the risk of developing migraine and increase the risk of severe migraine episodes. Anyone with hypothyroidism should tell a doctor if they experience a migraine episode for the first time or worsening episodes.

Treatment for hypothyroidism involves taking a synthetic version of the hormone that the thyroid is not producing. A common medication for this purpose is called levothyroxine (Levoxyl, Synthroid).

Many people with hypothyroidism and migraine report an improvement in migraine symptoms after they start taking levothyroxine. This suggests that the two health conditions may be linked for some people. Others continue to have migraine episodes after successful hypothyroidism treatment.

It is important to note that headaches are a common side effect of levothyroxine, if the dosage is too high or low. Anyone taking a high dosage of this medication may experience more frequent or severe headaches. If headaches arise during levothyroxine treatment, let a healthcare professional know.

Anyone with hypothyroidism and severe or frequent migraine episodes, or any other type of headache, should let a doctor know. They can determine whether to adjust the dosage of medication or suggest other treatments.

Also let a doctor know about a history of migraine and any symptoms of, or family history of, hypothyroidism. To test for this condition, a doctor sends a blood sample to a lab.

Hypothyroidism develops when the thyroid gland does not produce enough of its hormones. Experts are unsure whether there is a link between this condition and migraine, a neurological disorder.

Neither migraine nor hypothyroidism are life threatening, but they can reduce the quality of life. Treatments are available for both conditions.

Levothyroxine is a common medication for hypothyroidism. While most people who have migraine and take this hypothyroidism medication report a reduction in their migraine symptoms, some people experience headaches as a side effect. Anyone with hypothyroidism and migraine, or any other headache, should contact a healthcare professional.