Magnesium Oxide
Magnesium Oxide is an inorganic magnesium compound with the formula MgO and a molar mass of 40.30 g/mol. It is a white, odourless powder that is hygroscopic in moist air and very slightly soluble in water.
The compound carries the highest elemental magnesium content of any common magnesium source, at 60.3 percent by weight, which is the single reason it dominates the cost-per-milligram tier of the supplement market. The same low cost and high density also make it the standard magnesium feedstock for refractories, fertilizer, and rubber compounding.
We source bulk Magnesium Oxide from top China manufacturers for our partners, working with several of them. The manufacturers are in Hebei, Guangxi and Jiangsu. A smaller requirement can ship in a combined container with other ingredients.
Please send the grade you need, the volume and your destination port, and we will come back with a solution and a price.
or call +86-21-6858 0751
- Packaging
- 25 kg kraft paper bag with PE inner liner
- ISO 9001
- HACCP
- Halal
- Kosher
Specifications
| Item | Specification |
|---|---|
| Appearance | White odorless fine powder |
| Assay (ignited basis) | ≥ 96.0% |
| Magnesium content | ≥ 58.0% |
| Loss on ignition | ≤ 8.0% |
| Calcium oxide | ≤ 1.5% |
| Free alkali (as MgO) | ≤ 2.0% |
| Acid-insoluble matter | ≤ 0.1% |
| Chloride | ≤ 0.1% |
| Sulfate | ≤ 1.0% |
| Heavy metals (as Pb) | ≤ 3 mg/kg |
| Arsenic | ≤ 2 mg/kg |
| Particle size | Light or heavy grade, or per customer specification |
Common Markets Grades
Magnesium Oxide is classified primarily by reactivity, which is set by calcination temperature.
Light magnesium oxide, also called caustic-calcined magnesia, is calcined at 700 to 1000 °C. It has a high specific surface area, typically 20 to 200 m²/g, and reacts readily with water and acids. This is the format used for supplements, antacids, animal feed, and water treatment.
Hard-burned magnesia is calcined at 1000 to 1500 °C, with reduced surface area and slower reactivity. It serves as a slow-release magnesium source in fertilizer and in environmental remediation.
Dead-burned magnesia is calcined above 1500 °C until the periclase crystals sinter into a dense, low-reactivity material. It is the basis of basic refractory brick for steel and cement furnaces.
Fused magnesia is produced in electric-arc furnaces above 2800 °C and is used in high-purity refractories and in heating-element insulation.
USP, Ph. Eur., and FCC pharmaceutical and food grades sit in the light-magnesia bracket, with controlled limits on iron, calcium, soluble salts, and heavy metals.
Applications
- Oral magnesium supplements in capsule, tablet, and gummy form, where high elemental load per dose unit drives selection
- Antacid active in chewable tablets, often combined with simethicone
- Pharmaceutical excipient as a flow aid and acid neutraliser in solid-dosage forms
- Magnesium fortification of animal feed for cattle, sheep, and poultry to prevent grass tetany and support production
- Mineral fertilizer for magnesium-deficient soils, especially for citrus, banana, and tobacco crops
- Refractory brick and monolithic linings for basic-oxygen and electric-arc steelmaking furnaces, cement kilns, and glass furnaces
- Activator and acid scavenger in rubber and elastomer compounding, especially for chloroprene and chlorobutyl
- Insulation in mineral-insulated copper-clad cable and tubular heating elements
- Wastewater treatment as a slower-acting alternative to lime for heavy-metal precipitation
- Magnesia-based cements and decorative magnesium oxysulfate boards for construction
- Pulp and paper bleaching as an alkali source in peroxide stages
Brands Using Magnesium Oxide
Widely-distributed consumer products that list Magnesium Oxide on the ingredient label.
- Prestige Consumer Healthcare (Mag-Ox)Mag-Ox 400 Magnesium Oxide Tablets (483 mg Mg per tablet) ↗Pharmaceutical-grade magnesium oxide tablets supplying 482 mg elemental magnesium per dose.Label verified 2026-05-24
- Prestige Consumer Healthcare (Mag-Ox)Mag-Ox 400 (Prestige Brands product page) ↗Official brand-owner product page for Mag-Ox 400 magnesium oxide supplementLabel verified 2026-05-24
- Nature MadeNature Made Magnesium 250 mg Tablets (as Magnesium Oxide) ↗Active ingredient: magnesium oxide providing 250 mg magnesium; supports muscle, nerve, bone, and heart health; gluten free, no synthetic dyesLabel verified 2026-05-24
- Nature MadeNature Made Extra Strength Magnesium Oxide 400 mg Softgels ↗Softgel formulation providing 400 mg magnesium as magnesium oxide; supports muscle, nerve, bone, and heart functionLabel verified 2026-05-24
Brand names, product names and logos are the property of their owners. They appear here as published evidence that the ingredient is used, taken from the brand's own label or website. Their appearance is not an endorsement, and it does not mean the brand buys from us or from any manufacturer listed on this site.
China Manufacturers of Magnesium Oxide
Top Magnesium Oxide manufacturers in China.
Gangxi Yunbo Health Technology Co., Ltd.10 ingredients in the directory
Hebei Meishen Technology Co., Ltd.4 ingredients in the directory
Hebei Messi Biology Co., Ltd.4 ingredients in the directory
Thermphos7 ingredients in the directory
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
How We Help Source Magnesium Oxide
Direct Factory Sourcing
We run the whole process: selecting the manufacturer from the top Chinese food ingredient producers, negotiating the price, verifying quality, and coordinating the logistics. You deal with us instead of with several factories at once.
Original Packaging and Documents from the Manufacturer
The manufacturer sends your Magnesium Oxide out of its own factory in the original packing, through to your destination port. The COA, COO, MSDS, TDS and any certifications reach you from the manufacturer as well.
Free Samples and Lead Time
We send 100 to 500 g free for your own laboratory to test and you cover only the courier, usually within 2 to 3 working days. ETD is usually within 7 to 15 days once the order is confirmed, and we check that date against the factory's own manufacturing schedule before we give it to you.
Combined Shipment
We can load Magnesium Oxide together with other ingredients such as Sodium Acetate, Calcium Citrate and Sodium Lactate into one 20' FCL. If your quantity is small, we can also ship LCL.
Regulatory Status
Magnesium Oxide is approved for food, supplement, and pharmaceutical use in essentially every regulated market.
In the European Union it carries the additive number E530 as an anti-caking and acidity-regulating agent, with quantum satis authorisation in defined categories. The light form is listed on Annex II of Regulation (EU) 1170/2009 as a permitted magnesium source in food supplements.
The U.S. Food and Drug Administration recognises the substance as GRAS under 21 CFR 184.1431, with provision for direct addition to food, and as an OTC antacid under the established stomach-acid monograph.
JECFA has reviewed magnesium salts as a group and assigned them acceptable status for use as food additives.
Pharmacopoeial monographs appear in the United States Pharmacopeia (USP), the European Pharmacopoeia (Ph. Eur.), and the Japanese Pharmacopoeia (JP). Halal and Kosher certifications are routine.
Manufacturing Process
Two industrial routes account for almost all global supply.
The dominant route calcines naturally occurring magnesite, MgCO₃, mined in China, Russia, Turkey, Slovakia, Brazil, and North Korea. Crushed magnesite is fed to rotary or shaft kilns at temperatures matched to the target grade, releasing carbon dioxide and leaving magnesium oxide. Calcination temperature alone selects between light, hard-burned, and dead-burned products.
The synthetic route precipitates magnesium hydroxide from seawater or brine using lime, then calcines the dewatered Mg(OH)₂ to MgO. The Premier Periclase plant in Ireland and the Martin Marietta plant in Manistee, Michigan are long-standing examples. Seawater-derived MgO carries lower iron and boron than most natural magnesite, which makes it the preferred feed for pharmaceutical and high-performance refractory grades.
Fused magnesia is produced by re-melting either feedstock in three-phase electric-arc furnaces, which yields large, low-impurity periclase crystals that are crushed and graded for end use.
