Magnesium for Migraines: Does It Help, Which Form, and How Much
Marianne asked me on a Reset Room call whether anything on blood work explains why a person gets migraines, and whether there is a form of magnesium that helps with them. The second question has a cleaner answer than the first, so I will start there.
Does magnesium help migraines?
Yes, for prevention. Taken daily, magnesium reduces how often migraines come, and the American Academy of Neurology and the American Headache Society rate it “probably effective” for preventing episodic migraine. It does nothing once an attack has started. The strongest evidence is in people who get an aura before the pain, and in women whose migraines track their cycle.
The trial most people cite is a German one from 1996. Eighty-one migraine patients took 600 mg of magnesium a day or a placebo for twelve weeks. By weeks nine to twelve, attacks were down 41.6 percent in the magnesium group and 15.8 percent in the placebo group. Days with migraine fell, and so did the amount of painkiller people needed. The main side effect was diarrhea, in about one in five, which is the dose finding its ceiling.
I have a soft spot for magnesium because of how it works. It is not numbing anything. It is addressing one of the mechanisms that sets a migraine off, and it is cheap, and it is safe for anyone whose kidneys are healthy.
What actually happens during a migraine?
In broad strokes, this. A classic migraine is preceded by an aura, something that tells you a migraine is coming. Some people see squiggly lines. Some get a ringing in their ears, or a tingling in one hand. It is usually one-sided. During the aura, a slow wave of altered electrical activity moves across the surface of the brain, and blood flow to that region drops with it. If the wave crosses the visual part of the brain at the back of your head, neurons there fire on their own, and you see the squiggles.
Then the brain’s protective response kicks in. The blood vessels around it open wide, the pain fibres that wrap those vessels fire, and the aura fades as the pulsating headache arrives. That pulsation is the vessels. Magnesium matters at both ends of that, because a vessel wall is muscle, and muscle needs calcium to contract and magnesium to relax.
The other end is brain chemistry. Think of your brain as a room with a light switch and a dimmer. Glutamate turns the light on. GABA turns it off. Serotonin, dopamine and norepinephrine are dimmers that make it brighter, and glycine is a dimmer that turns it down. A migraine, in one description, is neurons that fire too easily. Magnesium sits inside the gate of the main glutamate receptor and keeps it from opening too readily. When magnesium is low, that gate opens on less provocation. That is why monosodium glutamate, MSG, is a reported trigger. Notice the word glutamate.
Why can’t you take magnesium once a migraine starts?
Because your stomach has stopped moving. During a migraine your gut slows right down, so a tablet sits there and does not get absorbed. That is why an aspirin or an Advil so often fails to touch a migraine, and why several of the dedicated migraine drugs are made as nasal sprays and injections, routes that bypass the stomach entirely. A 2006 study in the journal Headache found that stomach emptying is slow in migraine sufferers even between attacks.
So magnesium is a preventive. You take it every day, whether or not you have a headache, and you judge it over two or three months. In the German trial the benefit showed up in weeks nine to twelve, not week one.
Which magnesium is best for migraines?
Magnesium glycinate or magnesium threonate, because those are the forms that get into the brain. Glycine is itself an inhibitory neurotransmitter, it crosses the blood-brain barrier, and it drags the magnesium across with it. Threonate was designed for the same job; it is patented and costs more, and in my experience glycinate does it just as well. Citrate has a harder time reaching the brain, in my practice, though for honesty’s sake the prevention trials used citrate and a form called pidolate and still found a benefit. The form to avoid is oxide, which mostly stays in the gut. I have gone through the forms side by side in magnesium glycinate vs citrate.
Someone with migraines should be taking magnesium glycinate or threonate, because it is going to carry that magnesium across the blood-brain barrier.
How much magnesium should you take for migraines?
Start at 400 mg of elemental magnesium a day. The prevention trials used 360 to 600 mg, and if your blood work shows you are low, 800 mg a day is reasonable. The dose that gives you loose stools is one step too far; drop back to the one below it. Elemental is the number to watch on the label, because a 750 mg magnesium glycinate capsule delivers only about 95 mg of actual magnesium, which is why many people need two or three capsules, or a powder, to get there.
Why do migraines come with your period, and does magnesium help?
Women who get migraines around their period tend to run low on magnesium, and this is the group where supplementing has the clearest record. In a 1991 trial, women with menstrual migraine took 360 mg of magnesium a day from mid-cycle until their period, for two months. They had fewer days with headache, their premenstrual complaints eased, and the magnesium inside their white blood cells, which had been low, came up.
I will add one thing I see in practice. Chocolate is high in magnesium, and a lot of women who get cyclical migraines crave it in the days before. I treat that as a hint. It is not a diagnosis, any more than the red-meat craving of an iron-deficient patient is one. Listen to your body; then check the number.
What triggers should you look at?
- MSG and artificial sweeteners. The research on both is mixed, but enough of my migraine patients notice them that I always ask.
- Low blood sugar. If you are insulin resistant, your blood sugar swings up and down after meals, and when the fuel supply to your brain dips, your body uses blood pressure to push more through. Enough pressure above the neck, where your pressure sensors sit, and you have a migraine.
- Low iron, or anemia. Anything that interferes with how oxygen gets delivered to the brain can be part of the story.
Is there a blood test for migraines?
No. There is no marker that says migraine. What I do with a migraine patient is look at the things that affect fuel delivery to the brain, which is oxygen and glucose. That means inflammatory markers, fasting insulin and A1c for insulin resistance, and ferritin and a blood count for iron. None of those diagnoses a migraine. Each of them is a lever that, pulled the right way, makes one less likely.
The simplest lever is still the daily magnesium. Four hundred milligrams of glycinate, every day, for three months, and keep a diary. If the attacks thin out, you have your answer.
References
- Holland, S., Silberstein, S. D., Freitag, F., Dodick, D. W., Argoff, C., & Ashman, E. (2012). Evidence-based guideline update: NSAIDs and other complementary treatments for episodic migraine prevention in adults. Neurology, 78(17), 1346–1353. https://doi.org/10.1212/WNL.0b013e3182535d0c
- Peikert, A., Wilimzig, C., & Köhne-Volland, R. (1996). Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study. Cephalalgia, 16(4), 257–263. https://doi.org/10.1046/j.1468-2982.1996.1604257.x
- Facchinetti, F., Sances, G., Borella, P., Genazzani, A. R., & Nappi, G. (1991). Magnesium prophylaxis of menstrual migraine: effects on intracellular magnesium. Headache, 31(5), 298–301. https://doi.org/10.1111/j.1526-4610.1991.hed3105298.x
- Aurora, S. K., Kori, S. H., Barrodale, P., McDonald, S. A., & Haseley, D. (2006). Gastric stasis in migraine: more than just a paroxysmal abnormality during a migraine attack. Headache, 46(1), 57–63. https://doi.org/10.1111/j.1526-4610.2006.00311.x
