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E530 Magnesium oxide (Magnesia)

E530Acidity regulatorsOrigin: Mineral
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The short answer
Magnesium oxide (E530) is a white mineral powder that keeps cocoa and drink powders from clumping and adds magnesium to fortified foods. It's safe in food amounts, though large supplement doses act as a laxative.
Generally safe

Fine for most people at normal amounts.

E-numberE530
Comes fromMineral
What it doesAcidity regulators
Glycemic index—
Daily limitNot set
Also calledE530, Calcined magnesia

Rules by country

🇺🇸 US FDAApproved
🇪🇺 European UnionApproved
🇨🇦 Health CanadaApproved
CaliforniaNo extra rules

Permitted in the US, EU and Canada as an acidity regulator and anticaking agent. It is also a mineral source in fortified foods and supplements.

Daily limit: Experts haven’t set a number because normal food amounts are far below any level of concern.

What is it?

Magnesium oxide is a simple mineral compound. In food it works as a drying agent and acidity controller, and it adds a small amount of magnesium. The body absorbs less of it than it does from organic forms like magnesium citrate.

Where it comes from: Made by heating magnesium carbonate or magnesium hydroxide, which come from mined magnesite or from seawater, until they break down into a white powder.

Why it’s in food

  • Stops cocoa and powdered drinks clumping
  • Controls acidity in some processed foods
  • Adds magnesium to fortified foods
  • Serves as a mineral source in supplements

Often found in

Cocoa powderPowdered drink mixesFortified foodsSupplement tablets

Also listed as: E530, Calcined magnesia, Magnesium monoxide

Health & gut impact

Magnesium intakeBenefit

Magnesium supports muscle and nerve function, and many adults fall short of the recommended intake. Fortified foods help close part of that gap.

NIH Office of Dietary Supplements, magnesium fact sheet

Laxative effectConcern

Large supplement doses draw water into the bowel and act as a laxative, so high-dose products can cause loose stools.

NIH Office of Dietary Supplements, magnesium fact sheet

What can I use instead?

Magnesium carbonate (E504)

Ratio: About 1:1 by weight

Best for: Anticaking in powders

Related

More acidity regulators:

Acetic acid E260Acetic acid (E260) is the acid that makes vinegar sour. Diluted in food it is considered safe. The hazard is the concentrated factory form, not a splash of vinegar.Generally safeAmmonium carbonate E503Ammonium carbonate (E503) is a traditional leavening agent that makes thin cookies and crackers crisp. It breaks down into gas in the oven, so little of it stays in the finished food.Generally safeCalcium carbonate E170Calcium carbonate (E170) is ground limestone, the same calcium found in antacids. It adds calcium to plant milks and flour and is very safe.Generally safeCalcium chloride E509Calcium chloride (E509) is a salty calcium salt that firms tofu, cheese curds and pickles. It is considered safe at food doses. Too much tastes bitter, which is why recipes use a little.Generally safe

Common questions

Is magnesium oxide safe?

Yes at normal food levels. Supplement doses can loosen the stool, which is the most common side effect.

Is magnesium oxide vegan?

Yes as an ingredient. Some supplement capsules use animal gelatin, so check the capsule rather than the powder.

Is Magnesium oxide safe?

Generally safe (88/100). Permitted in the US, EU and Canada as an acidity regulator and anticaking agent. It is also a mineral source in fortified foods and supplements.

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Scientific sources & regulatory citations
  • 21 CFR 184.1431 (US FDA)
  • EFSA OpenFoodTox: E530
  • NIH Office of Dietary Supplements, magnesium fact sheet

INS 530 · CAS 1309-48-4