If you live with migraine, you know it’s never “just a headache”. For some, it begins with flickering lights or visual disturbance. For others, it arrives with nausea, sensitivity to sound or pain that feels as though it presses pause on the entire day. Over the past few decades, researchers have explored a nutrient that may quietly influence migraine susceptibility in some individuals: magnesium. Here is what the science says.

Magnesium and your brain

Magnesium is involved in more than 300 enzymatic reactions in the body. It supports ATP (energy) production, stabilises cell membranes and regulates how nerves communicate with one another. In simple terms, it helps your cells remain calm and energised simultaneously.

In migraine, the brain is thought to be more excitable. The threshold for triggering a cascade of events appears lower. One of those events is something called cortical spreading depression, a wave of electrical activity that travels across the brain and is associated with migraine aura. Magnesium helps regulate the NMDA receptor, which influences excitatory signalling. When magnesium levels are suboptimal, this receptor becomes more easily activated. That increased excitability may lower the threshold for migraine in susceptible individuals.

In animal and laboratory research, magnesium has been shown to block this spreading depression. In clinical practice, this translates into a simple idea: adequate magnesium may help calm a brain that is prone to overreacting.

Pain signalling and CGRP

Migraine involves more than electrical changes. It also involves neuropeptides such as CGRP, which is released from trigeminal nerves and contributes to pain and blood vessel dilation. Interestingly, magnesium appears to influence the release of CGRP and serotonin, both of which are involved in migraine development. Low magnesium may amplify pain signalling. Adequate magnesium may help modulate it. This doesn’t mean magnesium prevents all migraines. But it does suggest it plays a role in the biochemical terrain in which migraine develops.

Are magnesium levels lower in people with migraine?

This is where it becomes nuanced. Routine blood tests almost always show normal magnesium levels because only 1-2% of magnesium is actually found in the bloodstream – the rest of it is stored inside cells and in bone. Red blood cell magnesium appears to be a more useful test than serum. Magnesium in the blood also exists in different forms. Some of it is bound to proteins. Some is attached to other molecules. Only a portion is present as ionised magnesium – the free, active form that cells can immediately use.

It’s this ionised magnesium that helps regulate nerve signalling, stabilise blood vessels and calm excitatory pathways in the brain. More detailed assessments have found that many people with migraine, particularly during an acute attack, have lower levels of ionised magnesium even when their total magnesium appears normal on routine testing. In one study, around 50% of people experiencing an acute migraine had low ionised magnesium. Interestingly, those with lower active magnesium levels were also more likely to respond to intravenous magnesium treatment. In women with menstrually related migraine, magnesium insufficiency appears even more common.

When we consider that stress increases magnesium utilisation, caffeine increases its excretion, hormonal shifts influence its retention and poor sleep raises demand, it becomes easier to understand how modern life may quietly lower the threshold for migraine in susceptible individuals.

Hormonal fluctuations influence magnesium retention. Estrogen affects how magnesium is absorbed and utilised. As estrogen shifts across the menstrual cycle, magnesium status can shift alongside it. In women with menstrual migraine, studies show that magnesium supplementation during the luteal phase can reduce headache days and severity. For some women, this is a simple yet powerful intervention.

What does the research say about supplementation?

Several studies have shown that 400–600 mg of magnesium per day can reduce migraine frequency in some individuals. However, not all forms are absorbed equally, and tolerance varies, plus mega-doses can disrupt magnesium’s ratio to other minerals, like calcium and potassium. Poorly absorbed forms may remain in the bowel and draw in water, which is why diarrhoea is a common side effect at higher doses. Often, this indicates the magnesium hasn’t been well utilised.

This is why absorption matters. Food-based or highly bioavailable forms tend to be gentler and more efficiently absorbed. When magnesium is delivered in a form the body recognises, it can often be effective at lower doses, reducing the likelihood of mineral ration and digestive upset. The goal isn’t simply more magnesium. It’s well-absorbed magnesium that your body can actually use.