About
What it is and where it shows up.
Magnesium oxide (MgO) is a white, odourless inorganic powder produced by calcination of magnesite or magnesium hydroxide. In food it functions as an acidity regulator, anti-caking agent, firming agent, and a bioavailable source of the essential mineral magnesium.
Safety summary
The regulatory and scientific consensus.
Magnesium oxide has been affirmed GRAS by the FDA with no numerical ADI established, indicating a broad safety profile at typical food-use levels; JECFA likewise assigned an ADI 'not specified'. Excessive intake can cause osmotic diarrhoea and gastrointestinal discomfort due to unabsorbed magnesium ions. Individuals with impaired renal function are specifically at risk of hypermagnesaemia and should restrict intake.
Regulatory landscape
What food-safety regulators have decided.
| Jurisdiction | Status | Note |
|---|---|---|
| EFSA (European Food Safety Authority) (European Union) | Approved | Permitted as E530 in Annex II of Regulation (EC) No 1333/2008 as an acidity regulator and anti-caking agent at quantum satis (GMP) levels. Subject to re-evaluation under Commission Regulation (EU) No 257/2010.source |
| FSSAI (Food Safety and Standards Authority of India) (India) | Approved | INS 530 permitted in salt (table salt, iron-fortified salt, iodized salt) at GMP under FSS (Food Products Standards and Food Additives) Regulations, 2011. Also permitted as a processing aid at GMP in fruit/vegetable juices, fruit nectars, syrups, and wine per FSSAI Appendix C (2023/2025).source |
| FDA (Food and Drug Administration) (United States) | Approved | Affirmed GRAS under 21 CFR §184.1431; permitted as a miscellaneous and nutrient additive at GMP (good manufacturing practice) levels. Also listed in FDA's Substances Added to Food (EAFUS) database.source |
Who should approach with care
Whose guidance would steer them away.
Kidney Disease — Impaired kidneys cannot adequately excrete excess magnesium, raising the risk of hypermagnesaemia, which can cause neuromuscular depression, cardiac arrhythmias, and respiratory failure.
Ibs — Unabsorbed magnesium ions exert an osmotic laxative effect in the gut, which may aggravate diarrhoea-predominant IBS symptoms.
Ibd — The osmotic and mild alkalising action of magnesium oxide may irritate an already inflamed gastrointestinal mucosa in IBD patients.
Heart Disease — Patients with congestive heart failure or those on cardiac medications (e.g., digoxin) may have altered magnesium homeostasis; supplemental magnesium intake from food additives should be medically supervised.
Research citations
The sources behind this verdict.
- 1FDA. FDA GRAS Notice 806 for Dolomite – references magnesium oxide GRAS status (21 CFR §184.1431). fda.gov
- 2FDA. Code of Federal Regulations Title 21, Part 184.1431 – Magnesium Oxide. accessdata.fda.gov
- 3FDA. FDA Substances Added to Food (formerly EAFUS) – Magnesium Oxide entry. hfpappexternal.fda.gov
- 4FSSAI. FSSAI Food Safety and Standards (Food Products Standards and Food Additives) Regulations 2011 – Appendix C (Processing Aids, INS 530), 2025. fssai.gov.in
- 5EFSA. Re-evaluation programme for food additives permitted in the EU before 20 January 2009 – Commission Regulation (EU) No 257/2010, 2010. food.ec.europa.eu
- 6other. Opinion of the Scientific Committee on Food on the Tolerable Upper Intake Level of Magnesium – European Commission SCF, 2001.
Independently researched6 citations