Magnesium deficiency and migraines

If we asked the classic “you can take only one non-drug therapy for migraine to a desert island” question, the answer would easily be magnesium.  Magnesium activates hundreds of enzymes, plays several key roles in nerve and smooth muscle physiology, and is known for its calming effect on both muscle and nerve.  For those with migraines, a magnesium deficiency may:

-cause blood vessels to constrict, which can initiate the migraine process

-affect serotonin and other neurotransmitters levels, which can lower the threshold for onset of migraine

-promote cortical spreading depression, a key mechanism in migraines with an aura.

Unfortunately, 70-80% of North Americans have lower than desirable magnesium levels, with those suffering migraines showing the greatest deficit.  And not surprisingly, almost 50% of those with migraine had meaningful improvement with magnesium supplementation.  Since low magnesium also affects health1 and even longevity2 in so many ways, supplementing magnesium is almost a ‘no-brainer’ for those with migraines.  I usually make it one of my first go to nutrients in the pre-pharmaceutical management of migraine.

Testing for magnesium levels:

It’s not always necessary to test for magnesium levels before starting therapy, but if you have conditions that may have depleted your whole-body stores, getting a level can give a sense of what you may need, and tell us whether IV repletion may be an useful option.  A regular serum magnesium test is rarely helpful, however, because most of your body’s magnesium is not in the blood, it is intracellular.  Because of this, a regular magnesium test requires severe whole-body depletion before it becomes abnormal.  The test to consider would be what we call a RBC magnesium level, as red cell content is a better reflection of total stores. Most regular labs like Labcorp or Quest can get done this for you.

How to supplement magnesium:

  1. Acute infusion for early or refractory migraine: with an IV using magnesium sulphate ~1-2 grams.  Can be done in ER or office setting.  Also, 2-3 infusions over 1-2 weeks can restore low body levels much faster than oral supplementation
  2. Oral therapy. There are multiple options here, and you will see the relative merits of 4-5 different magnesium versions in online articles and advertisements. Here are the two that I’ve found most useful, and then …one to avoid:

-magnesium citrate.  This is one of the simplest forms of well absorbed magnesium, and is easy to find and use in its powdered form.  With the powder you can change the dose easily, and that’s important with magnesium, as we want to raise the does gradually to what we call ‘bowel tolerance’.  You start with a lower dose, like 300 mg of the powder form, taken in water or juice in the evening.  Every 2-3 days you add another 150 mg or so to the daily dose until you get bowel movements that are just a little too loose, usually in a dosage range of 500-1200 mg/day.  Then you back off to where you have ~three easy to pass and not too watery movements per day.  This is where you are absorbing most of the magnesium and not much is left over to promote excess bowel motility, although some improvement there will help with the constipation that many people with migraines have.   Over time, as your whole-body magnesium levels improve, you will likely find that you can gradually reduce your dose to find the best long-term daily maintenance dose for you.  An easy to find brand of mag citrate powder is known as “Calm Powder”, which has 56 doses of 325 mg each for ~$20-24.

-magnesium taurate is elemental magnesium that has been chelated with an amino acid called taurine. Taurine is an amino acid which benefits several direct central nervous system conditions, including migraines.  It is also helpful in depression, vascular conditions, cognitive function and some neurodegenerative disorders.  Because of this, it may be a better form of magnesium over the long term for those with migraines.

It typically comes in 200 mg or 400 mg capsule sizes.  Use the same graduated dosing we discussed for the citrate form to find your bowel tolerance dosage.

-magnesium oxide is the most likely form you will see in products, partially as it is the least expensive to make.  It is however, relatively poorly absorbed, and the most likely to cause gastrointestinal symptoms.    I would avoid it.

  1. Topical absorption. Many with migraines find that absorbing magnesium through the skin is a relaxing way to improve their migraines, and may help forestall an acute event.  You can use:

-Epsom salts in a warm bath, typically ~1/2 lb in bathwater, soaking in it  for 20-30 minutes.

-magnesium oil, which can be applied most anywhere, and may help with an acute or emerging migraine if applied also to the neck and forehead.

  1. Dietary magnesium. Typically, one should start with dietary (whole food) supplementation for most nutrients, but with migraines you may need more daily magnesium intake than a regular diet can supply. It would make sense however to have a magnesium rich diet, and some of the foods that can supply this include:

-dark leafy greens like spinach and chard, where one cup of either contains ~40% of the recommended daily value of magnesium.

-seeds: including pumpkin, squash and almonds

-mackerel and tuna

-low-fat yogurt or kefir

-black beans and lentils


Who should be cautious about taking Magnesium

You and your doctor should monitor closely if:

-you have renal insufficiency or kidney failure.

-you take thiazide diuretics, or certain cancer chemo drugs.  These may alter the amount of magnesium lost in the urine and the levels may need regular monitoring.

Magnesium can also interact with the absorption of digoxin, the nitrofurantoin, quinolone (Cipro, Levaquin) or tetracycline antibiotics, as well as anti-malarials, and some anticoagulants.


  1. Common associated symptoms seen with magnesium deficit: insomnia, irritable bowel syndrome, anxiety, fibromyalgia, chronic fatigue, muscle tension, sensitivity to loud noises, constipation and even obesity.
  2. Odds of dying roughly double in critical illness for those with magnesium deficiency. Magnesium deficiency in critical illness.  J Intensive Care Med. 2005 Jan-Feb;20(1):3-17.
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