E504II - Magnesium hydroxide carbonate

At a glance

• What it is: A mineral-based additive also known as basic magnesium carbonate
• What it does: Helps powders flow (anti-caking) and acts as a carrier for flavors or colors
• Where it appears: Dry mixes, seasonings, table-top products, and other powdered foods
• Vegan/vegetarian: Yes, it’s mineral-derived
• E-number: E504ii (part of the E504 magnesium carbonates group)
• Typical form: Fine, white powder with little to no taste

Why is Magnesium hydroxide carbonate added to food?

Manufacturers use it to prevent clumping in dry products and to help spread tiny amounts of flavorings or colorings evenly through a mix. In the U.S., “basic magnesium carbonate” is affirmed as GRAS (Generally Recognized as Safe) for use in food as an anticaking agent at levels consistent with good manufacturing practice.¹

What foods contain Magnesium hydroxide carbonate?

You’re most likely to find it in:

• Powdered mixes such as instant beverages, desserts, and meal replacements
• Seasoning blends and dry rubs
• Table-top products like powdered sweeteners or creamers
• Other dry goods where clump-free flow is important

On ingredient lists it may appear as “magnesium hydroxide carbonate,” “basic magnesium carbonate,” “E504,” or “E504ii.” It may also be grouped with other magnesium carbonates such as magnesium carbonate and the broader class magnesium carbonates.

What can replace Magnesium hydroxide carbonate?

Depending on the recipe and local rules, common swaps include:

• Silicon dioxide (E551) for anti-caking in spices and powders
• Tricalcium phosphate (E341iii) as an anti-caking agent in dry mixes
• Calcium silicate (E552) for moisture control and flow
• Calcium carbonate (E170i) in some dry blends
• Magnesium stearate (E572) for flow in tablets and certain foods

The best substitute depends on moisture level, pH, and the desired mouthfeel of the final product.

How is Magnesium hydroxide carbonate made?

Food-grade material is produced by reacting magnesium sources with carbonate and carbon dioxide, then filtering and drying the precipitated solid. EU specifications describe processes such as carbonating magnesium oxide in water or precipitating the compound from magnesium salts using carbonate, followed by purification and drying.²

Is Magnesium hydroxide carbonate safe to eat?

Yes. In the EU, it is an authorized food additive (E504) with detailed purity criteria set in Commission Regulation (EU) No 231/2012.² In the U.S., “basic magnesium carbonate” is affirmed as GRAS for use in food when used in accordance with good manufacturing practice.¹ As with other magnesium salts, very high intakes from supplements or medicines can cause diarrhea; people with kidney problems are more sensitive to excess magnesium.³

Does Magnesium hydroxide carbonate have any benefits?

Its benefits are technological: it keeps powders free-flowing and helps distribute minor ingredients evenly. While magnesium is an essential nutrient, the small amounts used as an additive are not a meaningful source of dietary magnesium.

Who should avoid Magnesium hydroxide carbonate?

• People with impaired kidney function should be cautious with all sources of supplemental magnesium, as their bodies may have difficulty clearing excess magnesium.³
• Individuals who experience digestive upset from magnesium-containing products may prefer foods that use different anti-caking agents.³

If you have a medical condition or take magnesium-containing medications or supplements, ask your healthcare provider about your total intake.

Myths & facts

• Myth: It’s the same as “milk of magnesia.” Fact: Milk of magnesia is magnesium hydroxide in water; magnesium hydroxide carbonate is a different, solid compound used in tiny amounts in foods.
• Myth: It’s synthetic and “chemical.” Fact: It’s a mineral-based compound produced from magnesium salts and carbon dioxide under controlled food-grade conditions.²
• Myth: It adds lots of magnesium to your diet. Fact: It’s used at very low levels, so it is not a significant source of magnesium.

Magnesium hydroxide carbonate in branded foods

You can spot it on labels as “magnesium hydroxide carbonate,” “basic magnesium carbonate,” “E504,” or “E504ii.” It appears most often in dry or powdered products where clumping is a concern. If you’re avoiding it, check the ingredient list on spice mixes, powdered drinks, and table-top products.

References

Footnotes

1. 21 CFR 184.1425 — Basic magnesium carbonate. U.S. Food and Drug Administration. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-184/section-184.1425 ↩ ↩²

2. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³

3. Magnesium Fact Sheet for Health Professionals. National Institutes of Health, Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ ↩ ↩² ↩³