Magnesium carbonate

E number E504INS 504(i)CAS 39409-82-0

Used as an acidity regulator — Codex also lists it as anticaking agent, carrier, colour retention, agent.

Magnesium carbonate is an anticaking agent, acidity regulator and magnesium source, used in powdered foods, table salt and cocoa processing.

Where it is and isn’t permitted

Status of Magnesium carbonate by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 184.1425retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

16 food categories

highest permitted level 15,000 mg/kg

Show every food category
  • 01.1.3 Fluid Buttermilk (plain) — GMP
  • 01.2.1.2 Fermented milks (plain), heat-treated after fermentation — GMP
  • 01.5.1 Milk powder and cream powder (plain) — GMP
  • 01.8.2 Dried whey and whey products, excluding whey cheeses — 10,000 mg/kg
  • 04.2.2.7 Fermented vegetable (including mushrooms and fungi, roots and tubers, pulses and legumes, and aloe vera) and seaweed products, excluding fermented soybean products of food categories 06.8.6, 06.8.7, 12.9.1, — 5,000 mg/kg
  • 06.2.1 Flours — 1,500 mg/kg
  • 09.2.2 Frozen battered fish, fish fillets and fish products, including molluscs, crustaceans, and echinoderms — GMP
  • 09.2.3 Frozen minced and creamed fish products, including molluscs, crustaceans, and echinoderms — GMP
  • 09.2.4 Cooked and/or fried fish and fish products, including molluscs, crustaceans, and echinoderms — GMP
  • 09.2.5 Smoked, dried, fermented, and/or salted fish and fish products, including molluscs, crustaceans, and echinoderms — GMP
  • 11.1.2 Powdered sugar, powdered dextrose — 15,000 mg/kg
  • 11.4 Other sugars and syrups (e.g. xylose, maple syrup, sugar toppings) — GMP
  • 12.1.1 Salt — GMP
  • 12.1.2 Salt substitutes — GMP
  • 12.2.1 Herbs and spices — GMP
  • 14.1.5 Coffee, coffee substitutes, tea, herbal infusions, and other hot cereal and grain beverages, excluding cocoa — GMP
CXS 192-1995 Table Three, INS 504(i)and 17 further provisionsretrieved 2026-09-07

What it is made from

Obtained by mining and refining magnesite, or precipitated from magnesium salt solutions.

  • Vegan
  • Vegetarian
CAS registry number
39409-82-0
InChIKey
UOVKYUCEFPSRIJ-UHFFFAOYSA-D
PubChem
CID 73415762

Every name it appears under

26 recorded names. A label may use any of them.

E number

  • E504

INS number

  • 504(i)
  • 504(ii)

CAS registry number

  • 12125-28-9
  • 39409-82-0
  • 546-93-0

As it appears in regulation

  • Magnesium carbonate

Other names

  • Basic magnesium carbonate
  • CARBONIC ACID, MAGNESIUM SALT (1:1), MIXT. WITH MAGNESIUM HYDROXIDE, HYDRATE
  • CCRIS 7884
  • E 504(i)
  • HYDRATED BASIC MAGNESIUM CARBONATE
  • HYDRATED BASIC MAGNESIUM CARBONATE (MART.)
  • Hydromagnesite
  • INS NO.504(II)
  • INS-504(II)
  • Kinsei
  • Magnesium carbonate
  • Magnesium carbonate basic
  • MAGNESIUM CARBONATE HYDROXIDE [MI]
  • Magnesium hydrogen carbonateMagnesium subcarbonate (light or heavy)Hydrated basic magnesium carbonateMagnesium carbonate hydroxide
  • Magnesium hydroxide carbonate
  • MAGNESIUM SUBCARBONATE (LIGHT OR HEAVY)
  • Marinco C
  • YQO029V1L4

Systematic names

  • Carbonic acid, magnesium salt (1:1), mixt. with magnesium hydroxide (mg(oh)2), hydrate

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07
  • gsfa retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/magnesium-carbonate.json