Magnesium oxide
1309-48-4 · Akro-mag · Animag · Anscor P · Calcined brucite · Calcined magnesia · Calcined magnesite · Cyclo/Mag · E 530 · Elastomag 100 · Elastomag 170 · Granmag · Heavy calcined magnesia · Heavy magnesia · Heavy magnesium oxide · INS NO.530 · INS-530 · INSTAMAG · KMB 100-200 · Kyowamag 100 · Light magnesia · Light magnesium oxide · Mag ox · Magcal · Magchem 100 · Magdose · Maglite D · Maglite de · Maglite K · Maglite S · Maglite Y · Magmilax bolus · Magnalax Bolus · Magnesa preprata · Magnesia · Magnesia monoxide · Magnesia oxydata · Magnesia USTA · Magnesii oxidum · Magnesium (as oxide) · Magnesium oxide · Magnesium oxide (MgO) · Magnesium Oxide 400mg · Magnesium oxide, heavy · Magnesium oxide, light · Magnezu tlenek · Magox 85 · Magox 90 · Magox 95 · Magox 98 · Magox OP · Magstar · Marmag · Megnesium Oxide · MVT Bolus · Oromag 160 · Oxide, Magnesium · Oximag · Oxymag · Seasorb · Seawater magnesia · SLO 369 · SLO 469 · Uro-Mag · E530 · 530 · oxomagnesium · Magnesium oxide · Magneesiumoksiid · Magnesium oxide · Magnesiumoksidi · Magnesiumoxid · Magnesiumoxide · Magnezijev oksid · Magnija oksīds · Magnio oksidas · Magnézium-oxid · Ossido di magnesio · Ossidu tal-manjeżju · Oxid de magneziu · Oxid hořečnatý · Oxyde de magnésium · Tlenek magnezu · Óxido de magnesio · ÓXIDO MAGNÉSICO · Οξείδιο του μαγνησίου · Магнезиев оксидE number E530INS 530CAS 1309-48-4
Listed as an acidity regulator and an anticaking agent by Canada, Codex and the US.
Listed as acidity regulators (CA, US, Codex) · anticaking agents (CA, US, Codex) · flavour enhancers (US) · humectants (US) · firming agents (US) · nutrient supplements (US) · flavouring agents and adjuvants (US) · formulation aids (US) · lubricants and release agents (US) · processing aids (US)
- Canada: Acidity regulator — Health Canada, List of Permitted Acidity Regulators and Acid-Reacting Materials (List 10)
- United States: pH control agent — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: pH control agents — 21 CFR 184.1431, citing 21 CFR 170.3(o)(23)
- Codex Alimentarius: Acidity regulator — CXS 192-1995 Table One, INS 530
- Canada: Anticaking agent — Health Canada, List of Permitted Anticaking Agents (List 1)
- United States: Anticaking agent or free-flow agent — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: Anticaking agents and free-flow agents — 21 CFR 184.1431, citing 21 CFR 170.3(o)(1)
- Codex Alimentarius: Anticaking agent — CXS 192-1995 Table One, INS 530
- United States: Flavor enhancer — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: Humectant — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: Firming agents — 21 CFR 184.1431, citing 21 CFR 170.3(o)(10)
- United States: Nutrient supplement — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: Nutrient supplements — 21 CFR 184.1431, citing 21 CFR 170.3(o)(20)
- United States: Flavoring agent or adjuvant — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: Formulation aid — FDA, Substances Added to Food: MAGNESIUM OXIDE
- United States: Lubricants and release agents — 21 CFR 184.1431, citing 21 CFR 170.3(o)(18)
- United States: Processing aid — FDA, Substances Added to Food: MAGNESIUM OXIDE

Magnesium oxide is an anticaking agent, acidity regulator and magnesium fortificant used in powdered foods and supplements.
Where it is and isn’t permitted
| Jurisdiction | Status | Scope and limits | Citation |
|---|---|---|---|
| Australia and New Zealand | Permitted, with conditions | 1 food category highest permitted level 10,000 mg/kg | Food Standards Code, Schedule 15, S15—5, item 1.5, INS 530retrieved 2026-10-17 |
| Canada | Permitted | no numerical limit (good manufacturing practice) 2 permitted uses Show every permitted use
| Health Canadaand 1 further provisionretrieved 2026-10-17 |
| European Union | Permitted, with conditions | 70 food categories highest permitted level 70,000 mg/l Show every food category
| Regulation (EC) No 1333/2008, Annex IIand 69 further provisionsretrieved 2026-10-18 |
| Great Britain | Permitted, with conditions | 68 food categories highest permitted level 70,000 mg/kg or mg/l Show every food category
| Assimilated Regulation (EC) No 1333/2008and 67 further provisionsretrieved 2026-10-18 |
| Japan | Permitted, with conditions | Designated additive: Appended Table 1, item 175, 酸化マグネシウム (“Magnesium Oxide” in the unofficial English translation). …Designated additive: Appended Table 1, item 175, 酸化マグネシウム (“Magnesium Oxide” in the unofficial English translation). Standards for use — Specifications and Standards for Foods, Food Additives, etc. (MHW Notification No. 370 of 1959), Part II (Food Additives), F (Standards for use): The Notification sets no standard for use (使用基準) for this additive, so it is not restricted there to particular foods or amounts. Compositional specifications for this additive, in the same Notification, are not imported and are not shown here; nor are the general rules in F 添加物一般, which apply to every additive. | Regulations for Enforcement of the Food Sanitation Act (MHW Ordinance No. 23 of 1948), Appended Table 1retrieved 2026-10-18 |
| South Korea | Permitted, with conditions | Designated food additive: Standards and Specifications for Food Additives, Part III, 1. …Designated food additive: Standards and Specifications for Food Additives, Part III, 1. 일반식품첨가물 (general food additives), 산화마그네슘 (“Magnesium Oxide”, the English the Code prints beside it); the Code marks it as also usable as a nutrient fortifier; 3. 영양강화제 (nutrient fortifiers), 산화마그네슘; nutrient: 마그네슘 (Mg); the Code marks it as also usable as a general food additive. Main use (주용도) of 산화마그네슘: 고결방지제, 산도조절제. Standard for use (사용기준) of 산화마그네슘: (1) [to be used under the general standard for use in II. 2. 1), the minimum amount that achieves the technical effect, with no limit set for this additive in particular] “II. 2. 1)의 규정에 따라 사용하여야 한다.” The Korean is the standard as published. There is no official English translation of the current Code (the English version on MFDS’s website is the 2020 edition and has no legal effect); the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications (Part IV) are not imported, nor are the general standards in Part II, which apply to every additive. | Standards and Specifications for Food Additives (식품첨가물의 기준 및 규격), MFDS Notification, Part III (Standards for use, by item)retrieved 2026-10-18 |
| United States | Permitted | 21 CFR 184.1431retrieved 2026-10-17 | |
| Codex Alimentarius | Permitted, with conditions | 5 food categories highest permitted level 10,000 mg/kg Show every food category and its notes
| CXS 192-1995 Table Three, INS 530and 5 further provisionsretrieved 2026-09-07 |
How much is permitted
A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.
| Australia and New Zealand | 10,000 mg/kg | 1 numeric limit |
|---|---|---|
| Canada | — | 2 GMP |
| European Union | 70,000 mg/kg | 1 numeric limit, 46 several limits, 1 quantum satis, 22 no quantity stated |
| Great Britain | 70,000 mg/kg | 1 numeric limit, 67 quantum satis |
| Japan | — | 1 no quantity stated |
| South Korea | — | 1 no quantity stated |
| United States | — | 1 no quantity stated |
| Codex Alimentarius | 10,000 mg/kg | 1 numeric limit, 5 GMP |
What it is made from
Produced by heating magnesium carbonate or hydroxide to drive off water and carbon dioxide.
- Vegan
- Vegetarian
Compare other additives on the dietary indexes.
- CAS registry number
- 1309-48-4
- InChIKey
- CPLXHLVBOLITMK-UHFFFAOYSA-N
- PubChem
- CID 14792
The two specifications, compared
The European Union sets identity and purity by regulation; JECFA publishes its own through FAO, advisory until a country adopts it. Both documents are below in full. These are the parameters each puts a number on.
| Parameter | European Union | JECFA |
|---|---|---|
| Assay | no less than 98 % | no less than 96 % |
| Loss on drying | — | no more than 5 % |
| Lead | no more than 2 mg/kg | no more than 2 mg/kg |
| Arsenic | no more than 3 mg/kg | — |
One parameter differs between the two documents. A difference is not a disagreement about safety: the two are revised on their own cycles, and an assay or a drying loss can be measured against a different preparation of the substance, which is why only the contaminant ceilings are marked. Within the EU the EU's figure is the one that binds.
How the EU defines it
The legal specification an additive must meet to be sold as this E number in the EU — what it is, how it may be made, and the purity it must reach. From Commission Regulation (EU) No 231/2012.
E 530 Magnesium oxide
Assay, identification and purity criteria
Description and assay
- Einecs
- 215-171-9
- Chemical name
- Magnesium oxide
- Chemical formula
- MgO
- Molecular weight
- 40,31
- Assay
- Content not less than 98,0 % on the ignited basis
- Description
- A very bulky, white powder known as light magnesium oxide or a relative dense, white powder known as heavy magnesium oxide. 5 g of light magnesium oxide occupy a volume of at least 33 ml, while 5 g of heavy magnesium oxide occupy a volume of not more than 20 ml
Identification
- Test for alkali
- Passes test
- Test for magnesium
- Passes test
- Solubility
- Practically insoluble in water. Insoluble in ethanol
Purity criteria
- Loss on ignition
- Not more than 5,0 % (ca. 800 °C to constant weight)
- Calcium oxide
- Not more than 1,5 %
- Arsenic
- Not more than 3 mg/kg
- Lead
- Not more than 2 mg/kg
How JECFA defines it
The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.
INS 530 Magnesium Oxide
Synonyms: INS No. 530
Assay, identification and purity criteria
Description and assay
- Specification history
- Prepared at the 17th JECFA (1973), published in FNP 4 (1978) and in FNP 52 (1992). Metals and arsenic specifications revised at the 57th JECFA (2001). An ADI not limited' was established at the 9th JECFA (1965)
- Chemical names
- Magnesium oxide
- C.A.S. number
- 1309-48-4
- Chemical formula
- MgO
- Formula weight
- 40.31
- Assay
- Not less than 96.0% after ignition at about 800 o
- DESCRIPTION
- Very bulky white powder, known as light magnesium oxide, or as a relatively dense, white powder, known as heavy magnesium oxide. 5 g of light magnesium oxide occupy a volume of 40 to 50 ml, while 5 g of heavy magnesium oxide occupy a volume of 10 to 20 ml.
- FUNCTIONAL USES
- Anticaking agent
- METHOD OF ASSAY
- tared platinum crucible. Weigh the residue accurately, dissolve in 25.0 ml of N sulfuric acid, boil gently to remove any carbon dioxide and cool. Add methyl red TS and titrate the excess acid with N sodium hydroxide. Subtract from the volume of N sulfuric acid consumed the number of ml of N sulfuric acid corresponding to the weight of CaO in the sample taken, using as a factor 28.04 mg of CaO for each ml of N sulfuric acid. The difference is the volume of N sulfuric acid used to neutralize the magnesium oxide and each ml is equivalent to 20.16 mg MgO.
Identification
- Solubility (Vol. 4)
- Practically insoluble in water; insoluble in ethanol
- Alkalinity
- The sample is alkaline to moistened litmus paper
- Test for magnesium (Vol. 4)
- Passes test
Purity criteria
- Loss on drying (Vol. 4)
- Not more than 5% after ignition at 800 o to 825 o to constant weight
- Alkali (free) and soluble salts
- Boil 2 g of the sample, weighed to the nearest mg, with 100 ml of water for 5 min in a covered beaker and filter while hot. Add methyl red TS and titrate 50 ml of the cooled filtrate with 0.1 N sulfuric acid. Not more than 2 ml of the acid should be consumed. Evaporate 25 ml of the filtrate to dryness and dry at 105 o for 1 h. Not more than 10 mg of residue should remain.
- Calcium oxide
- Not more than 1.5% Weigh 400 mg of the sample to the nearest 0.1 mg, and dissolve in a mixture of 3 ml of sulfuric acid and 22 ml of water. Add 50 ml of ethanol, and allow the mixture to stand overnight. If crystals of magnesium sulfate separate, warm the mixture to about 50 o to dissolve. Filter through a tared, previously ignited, porcelain filter crucible, and wash the precipitate several times with a mixture of 2 volumes of ethanol and 1 volume of dilute sulfuric acid TS. Ignite the crucible and contents at a dull red heat, cool and weigh. The weight of calcium sulfate obtained, multiplied by 0.4119, gives the equivalent of calcium oxide in the sample taken for the test.
- Lead (Vol. 4)
- Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.” Ignite about 400 mg of the sample to constant weight at 800 o to 825 o in a
Authorised in other additives, enzymes, flavourings and nutrients
These authorisations are not for use in food. They let this substance be used inside another additive, a food enzyme, a flavouring or a nutrient preparation — often as a carrier — and it reaches food only as part of that product. Annex III to Regulation (EC) No 1333/2008.
| Part | May be used in | Maximum level | Citation |
|---|---|---|---|
| Annex III, Part 2: Food additives other than carriers in food additives | All food additive preparationsAuthorised as a member of Table 1 of Part 6, listed as "Table 1" Note (1): Except enzymes authorised as food additives. | quantum satis | Regulation (EC) No 1333/2008, Annex III, Part 2, via Table 1 of Part 6 |
| Annex III, Part 3: Food additives including carriers in food enzymes | Food enzymesNote (1): Including enzymes authorised as food additives. | In enzyme preparation: quantum satis In final food except beverages: quantum satis In beverages: quantum satis | Regulation (EC) No 1333/2008, Annex III, Part 3 |
| Annex III, Part 4: Food additives including carriers in food flavourings | All flavouringsAuthorised as a member of Table 1 of Part 6, listed as "Table 1" | quantum satis | Regulation (EC) No 1333/2008, Annex III, Part 4, via Table 1 of Part 6 |
| Annex III, Part 5, Section A: Food additives added in nutrients except in nutrients intended to be used in foodstuffs listed in Part E, point 01.10, of Annex II and foodstuffs for infants and young children listed in Part E, point 13.1, of Annex II | All nutrientsCan be used as a carrier: Yes | quantum satis | Regulation (EC) No 1333/2008, Annex III, Part 5, Section A |
Every name it appears under
87 recorded names. A label may use any of them.
E number
- E530
INS number
- 530
CAS registry number
- 1309-48-4
As it appears in regulation
- Magnesium oxide
Other names
- Akro-mag
- Animag
- Anscor P
- Calcined brucite
- Calcined magnesia
- Calcined magnesite
- Cyclo/Mag
- E 530
- Elastomag 100
- Elastomag 170
- Granmag
- Heavy calcined magnesia
- Heavy magnesia
- Heavy magnesium oxide
- INS NO.530
- INS-530
- INSTAMAG
- KMB 100-200
- Kyowamag 100
- Light magnesia
- Light magnesium oxide
- Mag ox
- Magcal
- Magchem 100
- Magdose
- Maglite D
- Maglite de
- Maglite K
- Maglite S
- Maglite Y
- Magmilax bolus
- Magnalax Bolus
- Magnesa preprata
- Magnesia
- Magnesia monoxide
- Magnesia oxydata
- Magnesia USTA
- Magnesii oxidum
- Magnesium (as oxide)
- Magnesium oxide
- Magnesium oxide (MgO)
- Magnesium Oxide 400mg
- Magnesium oxide, heavy
- Magnesium oxide, light
- Magnezu tlenek
- Magox 85
- Magox 90
- Magox 95
- Magox 98
- Magox OP
- Magstar
- Marmag
- Megnesium Oxide
- MVT Bolus
- Oromag 160
- Oxide, Magnesium
- Oximag
- Oxymag
- Seasorb
- Seawater magnesia
- SLO 369
- SLO 469
- Uro-Mag
Systematic names
- oxomagnesium
Hazard reference values
| Type | Value | Population | Assessed by | Opinion |
|---|---|---|---|---|
| ADI | not limited | — | JECFA | 1965 |
Evidence and how bodies read it
Studies, and the differing conclusions regulators drew from them, are curated rather than machine-read, and none has been written for this substance yet.
Common questions
Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.
- What is E 530?
- E 530 is Magnesium oxide. Magnesium oxide is an anticaking agent, acidity regulator and magnesium fortificant used in powdered foods and supplements.
- What is Magnesium oxide used for in food?
- It is listed as an acidity regulator and an anticaking agent — the role Canada, Codex and the US assign it. This page shows every function each regulator records, with the citation for each.
- Where is Magnesium oxide permitted?
- Of the seven regulators this site reads, Australia and New Zealand, Canada, the EU, Great Britain, Japan, South Korea, the US and the Codex standard permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
- Is Magnesium oxide vegan?
- Yes. Magnesium oxide is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.
Sources for this page
- anz retrieved 2026-10-17
- ca retrieved 2026-10-17
- eu retrieved 2026-10-18
- gb retrieved 2026-10-18
- jp retrieved 2026-10-18
- kr retrieved 2026-10-18
- ecfr retrieved 2026-10-17
- gsfa retrieved 2026-09-07
- euspecs retrieved 2026-10-18
- jecfaspecs retrieved 2026-09-23
Full licence terms and publisher details on Sources. How this page is built and updated: Method.
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