You tried magnesium and felt nothing. Which form was in the bottle?

You are standing in the supplement aisle with a migraine on the horizon and a coupon in your pocket.

There are three magnesium bottles. One is cheap. You take the cheap one.

You take it for a month. Nothing changes. You decide magnesium is something other people get results from, and you move on.

Nobody told you there are different types of magnesium. Nobody told you the kind might matter. The honest answer is that nobody is entirely sure, and that is the part worth reading.

Magnesium glycinate vs magnesium oxide for migraine: the short answer

There is no head-to-head trial. We looked, and the sources we read do not contain one.

The migraine trials mostly used oxide or did not name the form. The case for magnesium glycinate for migraine rests on indirect reasoning about absorption and how well people tolerate it. Not on a study of glycinate for migraine.

So the best magnesium for migraines is not a question with a clean answer yet. Anyone telling you one form is proven for migraine is ahead of the evidence.

What the migraine guidelines and trials used

The American Migraine Foundation’s page on magnesium says magnesium oxide is commonly used for prevention, usually at 400 to 600 mg a day. It calls oxide inexpensive and available without a prescription.

It also says the American Academy of Neurology and the American Headache Society rated magnesium as probably effective in 2012. That rating is Level B, and the strongest evidence was in migraine with aura.

The NIH Office of Dietary Supplements fact sheet for health professionals says three of four small, short, placebo-controlled trials found modest drops in how often migraines happened, at up to 600 mg a day. It does not name the form used in those trials, and it calls the data limited.

We did not find glycinate named as the form in any guideline or trial we reached.

Magnesium oxide absorption: what the studies show

This is where the glycinate case comes from, and it is thinner than the marketing suggests.

A review in the journal Nutrients by Schuchardt and Hahn, comparing magnesium salts in humans, lists several small studies:

• In one study of 17 adults, citrate was absorbed significantly better than oxide.
• In another, of 20 men, citrate was only slightly higher than oxide, and the authors call the difference physiologically irrelevant.
• In a third, of 46 adults, citrate and an amino acid chelate both did better than oxide.

The authors conclude it remains unclear which form of magnesium is absorbed best. They argue that the dose, and your own magnesium status, may matter more than the salt.

There is no magnesium citrate vs glycinate migraine trial either. Glycinate is not named in these comparisons. We found no human absorption study for it in the sources we read.

Magnesium and migraine side effects: does the form matter?

Diarrhea is the common one. The American Migraine Foundation says it depends on the dose, and that lowering the dose or spacing it out usually helps.

The NIH fact sheet says high supplement doses cause diarrhea, nausea and cramping. It says the forms most often linked to diarrhea are carbonate, chloride, gluconate and oxide, because unabsorbed salt pulls water into the gut.

We did not find an NIH or American Migraine Foundation statement that glycinate is gentler. So that part of the marketing is also not proven in these sources.

How much magnesium for migraines, and the upper limit

This is the part to read twice.

The NIH sets a tolerable upper intake level of 350 mg a day for supplemental magnesium in adults. That limit applies to supplements, not to food.

The migraine doses in the trials, up to 600 mg a day, are higher than that. The NIH fact sheet says such doses should be used only under a health care provider’s direction. So the dose is not a do-it-yourself number.

The NIH also says people with impaired kidney function are at greater risk from excess magnesium. Some medicines interact with it, including certain antibiotics and bisphosphonates, so ask your pharmacist or doctor before you add magnesium.

Questions

Is magnesium glycinate or oxide better for migraines?

No head-to-head trial exists. The American Migraine Foundation says oxide is commonly used for prevention at 400 to 600 mg a day. The case for glycinate rests on indirect reasoning about absorption.

How much magnesium should I take for migraines?

The American Migraine Foundation says 400 to 600 mg a day of oxide is commonly used. That is above the NIH upper limit of 350 mg a day for supplements, so it should be used under a doctor’s guidance.

Does magnesium glycinate cause diarrhea?

Diarrhea depends on the dose, according to the American Migraine Foundation. The NIH lists oxide among the forms most often linked to it. We did not find an NIH or American Migraine Foundation source comparing glycinate directly.

Is magnesium oxide poorly absorbed?

Some small studies found citrate absorbed better than oxide, and others found little difference. Researchers say it remains unclear which form is absorbed best.

Can you take magnesium every day for migraines?

Daily use is how it is used for prevention, but the dose and the form should be set with a doctor, especially with kidney problems or interacting medicines.

How long does magnesium take to work for migraines?

We did not find a source that gives a set time. The trials the NIH describes were short, so ask your doctor what to expect for you.

Where the line comes in

Magnesium is one of the things people reach for when migraines keep coming. The better question comes first: how close your brain sits to the edge before the day even starts.

There is a name for that edge. The Migraine Tipping Line™.

Read what the Migraine Tipping Line™ is, and why your diary never found it →

For the early signs that arrive before the pain, see what is migraine prodrome.