Migraine Headaches and Thyroid Disease

According to the International Headache Society, around 30% of people with an underactive thyroid gland (hypothyroidism) have a history of headaches. Though the causes for this are poorly understood, women are disproportionately affected.

Headache pain associated with thyroid disease is usually unilateral (one-sided), pulsing, and often accompanied by nausea or vomiting. Moreover, half will have a history of migraines before their thyroid diagnosis. Symptom severity tends to rise and fall alongside the severity of the disease.

This article explains the correlation between migraine headaches and thyroid disease, risk factors, and treatment.

Headaches and Thyroid Symptoms

Hypothyroidism results from inadequate thyroid hormone production. Sufficient thyroid hormone is needed to regulate metabolism—the conversion of calories and oxygen to energy—so that the body has the fuel it needs to function optimally.

When you don't produce enough thyroid hormones, it can trigger a cascade of symptoms that affect metabolism. These symptoms may include:

• Weight gain
• Fatigue
• Brain fog
• Depression
• Mood swings
• Irregular menstruation
• Hair loss

Another common hypothyroidism symptom is a headache.

While it would be reasonable to assume that hypothyroidism "causes" headaches, it is still unclear whether the condition is the cause or consequence of headaches. The evidence is split.

Who Is at Risk?

Research has found a number of factors that elevate the risk of hypothyroidism and headaches.

Women

According to the Society for Endocrinology, women are 18 times more likely to have hypothyroidism than men. In addition, they are three times as likely to experience migraines (18% versus 6%, respectively, according to research from John Hopkins University). Within this population, around 55% of migraine events are related to menstrual periods.

While this may suggest that migraines result from hormonal fluctuations during menstruation, hypothyroidism is more common among people over age 60. However, this is when people have undergone menopause and should experience an alleviation—rather than an increase—of migraine symptoms.

Instead, migraines can persist well after menopause. This fact supports the theory that hypothyroidism is a critical contributing factor to migraine risk.

Pre-Existing Headaches

Some researchers have inferred that a history of headaches and migraines may predispose a person to hypothyroidism.

In a 2016 study published in the journal Headache, researchers medically monitored 8,412 people over 20 years. They excluded anyone with a prior history of thyroid disease or an abnormal thyroid reading at the start of the study.

The study found that those with pre-existing headache disorders had a 21% increased risk of new-onset hypothyroidism compared to people with no history of headaches. In addition, compared to the general population, people with a history of migraines (as opposed to tension-type headaches) had a 41% increased risk of new-onset hypothyroidism.

While this in no way suggests that headaches are the cause of hypothyroidism, it does imply that a history of headaches may place you at greater risk of hypothyroidism.

Headaches and Thyroid Treatment

Thyroid hormone replacement therapy, most typically in the form of levothyroxine, can help minimize hypothyroid symptoms. However, some people will still experience recurrent headaches even after treatment. So, again, whether or not the headaches are related to thyroid disease remains unclear.

In most cases, people with migraines and subclinical hypothyroidism (hypothyroidism with no observable symptoms) will see an improvement in headache symptoms after being placed on levothyroxine.

According to research presented at the Congress of the European Academy of Neurology in 2017, levothyroxine may reduce the frequency of migraines.

In the study, 45 people with subclinical hypothyroidism and migraines without aura (migraine without a visual or sensory warning) experienced a drop in migraine incidence after levothyroxine therapy. In this group, participants' migraines went from 14.68 attacks per month to 1.86 episodes per month.

It is unknown whether the same benefits would apply to people with overt (symptomatic) hypothyroidism. But, a study published in 2016 did find that people with both subclinical and overt hypothyroidism reported a similar relief from headaches with levothyroxine treatment.

It is also important to note that headache is a common side effect of levothyroxine use. In people with moderate to severe hypothyroidism, which would inherently require higher doses, the drug may, in fact, trigger headaches or worsen existing symptoms.

Summary

Headaches are common in people with hypothyroidism. It is unclear whether headaches are a side effect of an underactive thyroid or a risk factor for developing the condition. If you have hypothyroidism and migraines, thyroid hormone replacement levothyroxine may reduce the frequency of migraines. However, headaches are a common side effect of the medication.

A Word From Verywell

If levothyroxine does not improve your headaches or it makes them worse, you may need to treat your headache separately as a distinct disorder. In this case, a healthcare provider will want to diagnose your headache accurately. This process may involve blood tests, imaging studies, and treatment options like over-the-counter pain relievers, triptans, and ergot medications.