What causes migraine headaches?

Migraine headaches are a symptom of a condition known as migraine.

Doctors don’t know the exact cause of migraine headaches, although they seem to be related to changes in your brain and to your genes. Your parents can even pass down migraine triggers like fatigue, bright lights, or weather changes.

For many years, scientists thought migraines happened because of changes in blood flow in the brain. Most now think this can contribute to the pain, but is not what starts it.

Current thinking is that a migraine likely starts when overactive nerve cells send out signals that trigger your trigeminal nerve, which gives sensation to your head and face. This cues your body to release chemicals like serotonin and calcitonin gene-related peptide (CGRP). CGRP makes blood vessels in the lining of your brain swell. Then, neurotransmitters cause inflammation and pain.

Migraine Risk Factors

The American Migraine Foundation estimates that more than 38 million Americans get migraines. Some things may make you more likely to get them:


Women have migraines three times more often than men.


Most people start having migraine headaches between ages 10 and 40. But many women find that their migraines get better or go away after age 50.

Family history

Four out of five people with migraines have other family members who get them. If one parent has a history of these types of headaches, their child has a 50% chance of getting them.
If both parents have them, the risk jumps to 75%.

Other medical conditions

Depression, anxiety, bipolar disorder, sleep disorders, and epilepsy can raise your odds.

Migraine Triggers

Some common migraine triggers include:

Hormone changes

Many women notice that they have headaches around their period, while they’re pregnant, or when they’re ovulating. Symptoms may also be tied to menopause, birth control that uses hormones, or hormone replacement therapy.


When you’re stressed, your brain releases chemicals that can cause blood vessel changes that might lead to a migraine.


Some foods and drinks, such as aged cheese, alcohol, and food additives like nitrates (in pepperoni, hot dogs, and lunchmeats) and monosodium glutamate (MSG), may be responsible in some people.

Skipping meals

Skipping meals seems to have a negative effect.


Getting too much or not getting as much as you’re used to can cause headaches. Caffeine itself can be a treatment for acute migraine attacks.

Changes in weather

Storm fronts, changes in barometric pressure, strong winds, or changes in altitude can all trigger a migraine.


Loud noises, bright lights, and strong smells can set off a migraine.


Vasodilators, which widen your blood vessels, can trigger them.

Physical activity

This includes exercise and sex.


Tobacco use may cause headaches.

Changes to your sleep

You might get headaches when you sleep too much or not enough.