Quick Search
E528 Magnesium hydroxide is best known as the active ingredient in Milk of Magnesia, an antacid and laxative which has been used for 150 years.
E528 Magnesium hydroxide forms a suspension in water, and its reaction with acid only dissolves it gradually, giving it long-lasting effects.
E528 Magnesium hydroxides primary action is to hold water, as it is not absorbed by the large intestine, relieving constipation.
CAS Number: 1309-42-8
Molecular Formula: H2MgO2
Molecular Weight: 58.32
EINECS Number: 215-170-3
Synonyms: MAGNESIUM HYDROXIDE, 1309-42-8, milk of magnesia, magnesium dihydroxide, magnesium hydrate, magnesium hydroxide Mg(OH)2, magnesium II hydroxide, Phillips magnesia tablets, magnesium as hydroxide, Magnesii hydroxidum, INS NO.528, DTXSID4049662, Phillips milk of magnesia liquid, INS-528, NBZ3QY004S, CHEBI:6637, E-528, hydrate magnesium, 215-170-3, hydroxide magnesium, Magmex, Dulcolax liquid, gentle laxative, MagLax, Magmilax powder, antacid laxative, MVT powder, Walgreens children, LAXADE, MAGNALAX, MiraFAST soft chews, CVS Health children, milk of magnesia mint, RefChem:5971, Humco milk of magnesia, milk of magnesia cherry, milk of magnesia liquid, Sunmark milk of magnesia, Medibest milk of magnesia, milk of magnesia original, milk of magnesia concentrate, children oral saline laxative, Dulcolax soft chews watermelon, Sunmark milk of magnesia mint, Premier Value milk of magnesia, Equate kids gentle laxative, CareOne milk of magnesia cherry, DTXCID1029621, Dulcolax soft chews mixed berry, CHEBI:35149, Equate gentle laxative soft chew, CareOne milk of magnesia original, Phillips original milk of magnesia, Walgreens children saline laxative, CVS Health children saline laxative, Dulcolax chewy fruit bites, Phillips fresh mint milk of magnesia, CVS magnesium hydroxide laxative chew, Phillips wild cherry milk of magnesia, SUNMARK milk of magnesia original, Walgreens blue raspberry gentle laxative, Meijer magnesium hydroxide soft chew, Alcanex NHC 25, Baschem 12, caustic magnesite, Combustrol 500, Hydrofy G, Kisuma series, Mag Chem MH 10, MagneClear, Magnesia magma, magnesium hydroxide gel, magnesiumhydroxide, Mg(OH)2, SCHEMBL9173, CHEMBL1200718, MAGNESIUM HYDROXIDE II, MI, FCC, HSDB, VANDF, MART, USP-RS, WHO-DD, AKOS015904092, DB09104, MAGNESIUM HYDROXIDE EP MONOGRAPH, ORANGE BOOK, E528, magnesium hydroxide USP monograph, magnesium hydroxide EP impurity, magnesium hydroxide USP RS, magnesium hydroxide WHO-IP Latin, magnesium hydroxide NS00074456, C07876, F245956, Q407548, PEPCID COMPLETE component magnesium hydroxide, Magnesium hydroxide, min. 95%, 10-15 micron;Magnesium hydrate,high purity flameretardant;Magnesium hyroxide usp25;MAGNESIUM HYDROXIDE, POWDER;MAGNESIUM HYDROXIDE SIGMAULTRA;MAGNESIUM HYDROXIDE REAGENT GRADE 95%;MAGNESIUM HYDROXIDE, NANOPOWDER, 99.9%;MAGNESIUM HYDROXIDE 98+% 9UM
E528 Magnesium hydroxide is also used as a fire retardant and smoke repressor in various applications due to an endothermic decomposition reaction which takes place at 332°C, releasing magnesia and water.
Further applications include wastewater treatment, as a fuel additive, and production of magnesium salts.
E528 Magnesium hydroxide, known in the European Union by the food additive code E528, is a safe, odorless, white mineral compound used primarily as an acidity regulator, stabilizer, and firming agent in the food industry.
E528 Magnesium hydroxide is an excellent flame retardant for plastics and rubber products.
In environmental protection, it is taken as flue gas desulfurization agent and can replace the caustic soda and lime as the neutralizer of acid-containing waste water and the absorbent of the heavy metal.
E528 Magnesium hydroxide can also be used for the electronics industry, medicine, sugar refining, as insulation materials and for the manufacturing of other magnesium salt products.
E528 Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2.
It occurs in nature as the mineral brucite.
E528 Magnesium hydroxide is a white solid with low solubility in water (Ksp = 5.61×10−12).
E528 Magnesium hydroxide is a common component of antacids, such as milk of magnesia.
E528 Magnesium hydroxide is widely used in pharmaceutical applications, especially as an antacid and mild laxative, because it neutralizes excess stomach acid in a controlled way without causing rapid or aggressive pH changes, and it can also draw water into the intestines, helping relieve constipation in a gentle and medically controlled manner.
This makes it one of the most commonly used over-the-counter digestive relief compounds.
E528 Magnesium hydroxide improves gastrointestinal comfort and acid balance regulation.
In flue gas treatment systems, E528 Magnesium hydroxide is used to remove acidic gases such as sulfur dioxide by reacting with them to form magnesium sulfite or sulfate compounds, which helps reduce harmful emissions from industrial plants and power stations while producing relatively stable byproducts.
E528 Magnesium hydroxides slurry form allows efficient large-scale gas scrubbing applications.
E528 Magnesium hydroxide improves air pollution control and emission reduction efficiency.
In wastewater treatment, E528 Magnesium hydroxide is used to neutralize acidic effluents and stabilize pH levels, especially in systems where a slow-acting alkaline agent is preferred to avoid sudden changes that could disrupt biological treatment processes or microbial activity.
This controlled buffering action is important in sensitive treatment environments.
E528 Magnesium hydroxide improves wastewater stability and environmental safety.
E528 Magnesium hydroxide is used as a flame retardant filler in plastics and polymers because it decomposes at high temperatures to release water vapor, which helps cool materials and suppress combustion while also forming a protective magnesium oxide layer.
This makes it valuable in cable insulation and construction materials.
E528 Magnesium hydroxide improves fire resistance and material safety.
E528 Magnesium hydroxide is used as a filler and stabilizer that improves heat resistance and reduces smoke formation during combustion, which enhances the safety and performance of polymer-based products used in construction, electronics, and transportation industries.
E528 Magnesium hydroxide improves material durability and thermal stability.
In environmental remediation systems, E528 Magnesium hydroxide is used to treat acidic mine drainage and contaminated soils because it can gradually raise pH and promote precipitation of dissolved heavy metals, reducing their mobility and environmental toxicity in affected areas.
Its controlled solubility makes it suitable for long-term treatment applications.
E528 Magnesium hydroxide improves environmental restoration and contamination control.
E528 Magnesium hydroxide can be used as a acidity regulator or processing aid in limited applications, where it helps stabilize pH conditions without significantly altering taste or product composition.
All uses are strictly controlled to ensure safety compliance.
E528 Magnesium hydroxide improves controlled food processing stability.
In chemical manufacturing, magnesium hydroxide is used as a precursor for producing other magnesium compounds such as magnesium oxide and magnesium salts, which are important in industrial materials, ceramics, and specialty chemical production.
This makes it an important intermediate in magnesium chemistry.
E528 Magnesium hydroxide improves chemical production versatility.
E528 Magnesium hydroxide is also widely used in controlled buffering systems, where its very low solubility allows it to act as a “slow-release” base that prevents sudden pH changes, making it especially valuable in systems that must remain chemically stable over long periods, such as biological wastewater treatment tanks or environmental remediation sites where microbial activity is sensitive to rapid alkalinity shifts.
This gradual behavior is one of its most important functional advantages compared with stronger hydroxides.
E528 Magnesium hydroxide improves long-term pH stability and process control.
In industrial wastewater neutralization of heavy metals, magnesium hydroxide is used because it raises pH slowly enough to allow dissolved metals like lead, copper, and zinc to precipitate as hydroxides in a controlled way, reducing the risk of forming unstable sludge or causing shock reactions in treatment systems.
This makes it particularly effective in mining and metal-processing effluents.
E528 Magnesium hydroxide improves heavy metal removal efficiency and sludge quality.
E528 Magnesium hydroxide slurry is used to capture sulfur dioxide from exhaust gases, where it reacts to form magnesium sulfite and sulfate compounds, and its fine particle suspension allows good gas–liquid contact, making it efficient in large-scale emission control systems used in power plants and industrial furnaces.
Its slurry form also reduces scaling problems compared with some other lime-based systems.
E528 Magnesium hydroxide improves industrial emission control and operational reliability.
In polymer compounding and cable insulation materials, E528 Magnesium hydroxide acts as a halogen-free flame retardant, where it decomposes when exposed to heat and releases water vapor that cools the material surface and dilutes flammable gases, helping slow down combustion and reduce smoke production in fire conditions.
This makes it important in modern safety-focused material design.
E528 Magnesium hydroxide improves fire safety and smoke suppression performance.
Melting point: 350 °C (lit.)
Density: 2.36 g/cm3
Storage temp.: Room Temperature
Solubility: 5 M HCl: 0.1 M, clear, yellow
Form: powder
Specific Gravity: 2.36
Color: white
Odor: odorless
pH range: 9.5–10.5
pH: 10.4 (1 mM); 10.4 (10 mM); 10.4 (100 mM)
Water Solubility: 0.9 mg/100 mL (18 ºC)
Sensitive: air sensitive
λmax: λ 260 nm Amax 0.030; λ 280 nm Amax 0.025
Merck: 14,5670
Solubility Product Constant (Ksp): pKsp 11.25
Stability: stable
Cosmetics Ingredients Functions: ABSORBENT; BUFFERING
Cosmetic Ingredient Review (CIR): Magnesium hydroxide (1309-42-8)
InChI: 1S/Mg.2H2O/h;2*1H2/q+2;;/p-2
InChIKey: VTHJTEIRLNZDEV-UHFFFAOYSA-L
SMILES: O[Mg]O
LogP: -1.380 (est)
E528 Magnesium hydroxide is used as highly effective non-toxic inorganic flame retardant, filler, and smoke suppressant additive for production of plastics and filled (co)polymer compounds based on elastomers, thermosets, thermoplastics, including those based on polyvinylchloride, polyamides, polystyrene, polyethylene, polypropylene, polyethylene terephthalate, ultrathene, and so on, in paper and cardboard industry, as a mild neutralizing agent for waste and natural water treatment, as raw material in chemical and pharmaceutical industry.
Treating the solution of different soluble magnesium salts with alkaline water induces the precipitation of the solid hydroxide Mg(OH)2: Mg2+ + 2 OH− → Mg(OH)2 As Mg2+ is the second most abundant cation present in seawater after Na+, it can be economically extracted directly from seawater by alkalinisation as described above.
E528 Magnesium hydroxide, also known as milk of magnesia or Mg(OH)₂, is an inorganic weak alkaline compound that appears as a white solid and is widely used in pharmaceuticals, food processing (regulated use), water treatment, and industrial applications because of its mild alkalinity, low solubility in water, and ability to neutralize acids in a controlled and slower manner compared with stronger hydroxides.
It is considered a safer and more gentle base compared to sodium, potassium, or calcium hydroxides.
E528 Magnesium hydroxide improves its suitability for controlled biological and industrial applications.
E528 Magnesium hydroxide consists of magnesium ions (Mg²⁺) and hydroxide ions (OH⁻), and when it is placed in water it forms a suspension rather than a fully dissolved solution due to its very low solubility, which allows it to release hydroxide ions gradually and maintain a stable, mild alkaline environment.
This slow release of alkalinity is a key reason for its medical and buffering uses.
E528 Magnesium hydroxide improves controlled acid neutralization and buffering behavior.
E528 Magnesium hydroxide appears as a white, fine powder or suspension in water (milk-like liquid), and it is odorless, tasteless, and stable under normal storage conditions, although it can absorb carbon dioxide from air over time and slowly convert into magnesium carbonate.
Its low solubility distinguishes it from other hydroxides used in industry.
E528 Magnesium hydroxide improves stability and safe handling characteristics.
E528 Magnesium hydroxide functions mainly as a mild acidity regulator and antacid-type compound, where it neutralizes excess acids in systems while avoiding sharp pH spikes due to its limited solubility and gradual reactivity.
This makes it particularly useful in systems requiring gentle pH correction.
E528 Magnesium hydroxide improves safe acid neutralization and pH buffering.
E528 Magnesium hydroxide is also used in water treatment systems, where it helps neutralize acidic water and contributes to pH stabilization while also supporting precipitation of certain impurities in controlled conditions.
Its slow reactivity makes it useful in long-term stabilization processes.
E528 Magnesium hydroxide improves water quality control and environmental treatment efficiency.
E528 Magnesium hydroxide is best described as a mild, low-solubility alkaline compound used for controlled acid neutralization, buffering, and stabilization in pharmaceutical, food-related, water treatment, and industrial systems due to its slow-release hydroxide behavior and relatively safe chemical profile.
In ceramic and refractory material production, E528 Magnesium hydroxide is used as a precursor to magnesium oxide (MgO), which is a high-temperature resistant material used in furnace linings, crucibles, and insulating bricks, where thermal stability and resistance to chemical attack are required.
E528 Magnesium hydroxide transformation occurs during calcination at elevated temperatures.
This improves high-temperature material strength and durability.
In soil and environmental pH correction, it is used in acidic land restoration projects where its gradual dissolution helps neutralize acidity over time without causing sharp chemical stress to soil microorganisms, making it suitable for sensitive ecosystems such as agricultural land recovery and wetland restoration.
E528 Magnesium hydroxide slow action makes it environmentally safer than fast-acting alkalis.
This improves ecological restoration and soil recovery.
In magnesium chemical production, E528 Magnesium hydroxide is a key intermediate for producing magnesium oxide, magnesium salts, and other magnesium-based industrial compounds used in pharmaceuticals, ceramics, flame retardants, and specialty chemical manufacturing.
E528 Magnesium hydroxides role as a precursor makes it central in magnesium processing industries.
This improves industrial magnesium compound production efficiency.
In pharmaceutical formulation systems, beyond its antacid function, it is also used as a buffering and stabilizing excipient in some drug formulations to maintain pH conditions that preserve active ingredients and improve shelf stability without introducing highly reactive components.
E528 Magnesium hydroxides mildness makes it suitable for sensitive formulations.
This improves drug stability and formulation control.
In odor control and environmental deodorization systems, E528 Magnesium hydroxide is used to neutralize acidic odor compounds in wastewater treatment plants and waste storage facilities, where it helps reduce unpleasant smells by shifting chemical equilibria and neutralizing volatile acidic gases.
This is particularly useful in municipal waste systems.
This improves odor management and environmental comfort.
In research and materials science, E528 Magnesium hydroxide is studied as a model compound for layered hydroxide structures and nanomaterials, where it is used in the development of advanced adsorbents, catalysts, and functional materials with applications in environmental cleanup and energy systems.
Its layered structure allows modification at the nanoscale.
This improves materials research and advanced chemical design.
E528 Magnesium hydroxide is a mild, low-solubility alkaline compound used across environmental treatment, pharmaceuticals, flue gas cleaning, flame retardant materials, ceramics, soil remediation, and chemical manufacturing because of its slow-release alkalinity, stability, and ability to neutralize acids without causing rapid or aggressive chemical changes in sensitive systems.
Uses Of E528 Magnesium hydroxide:
E528 Magnesium hydroxide is an excellent flame retardant for plastics and rubber products.
In environmental protection, it can be used as flue gas desulfurization agent, being able to replace the caustic soda and lime as acid-containing waste water neutralizer.
E528 Magnesium hydroxide can also used as oil additive with anti-corrosion and desulfurization effect.
In addition, it can also be used for the electronics industry, medicine, sugar refining, for insulation materials and the manufacture of other magnesium salt products.
One important application of E528 Magnesium hydroxide is the use of the material in the pharmaceutical industry, for example as antacid to neutralize stomach acids and as laxative.
E528 Magnesium hydroxide is mainly used as a mild alkali, antacid, buffering agent, and industrial neutralizer because of its slow-release hydroxide ions and low solubility, which allow controlled acid neutralization without sharp pH changes.
In pharmaceuticals, it is used as an antacid to neutralize stomach acid and as a mild laxative.
This improves digestive system relief and acid balance.
In wastewater treatment, it is used to neutralize acidic water and stabilize pH levels in treatment systems.
E528 Magnesium hydroxide improves environmental water quality control.
In flue gas treatment, it is used to remove acidic gases such as sulfur dioxide from industrial emissions.
E528 Magnesium hydroxide improves air pollution control.
In plastic and polymer manufacturing, it is used as a flame retardant and stabilizer.
This improves fire safety and material performance.
In environmental remediation, it is used to treat acidic soils and mine drainage.
E528 Magnesium hydroxide improves contamination control and ecosystem recovery.
In chemical manufacturing, it is used as a precursor for other magnesium compounds.
E528 Magnesium hydroxide improves industrial chemical production.
In food processing (regulated use), it is used as a limited acidity regulator and processing aid.
This improves controlled pH management in food systems.
E528 Magnesium hydroxide is used as a flue gas desulfurization absorbent.
In the 20th century, before the 1970s, most flue gas desulfurization applied sodium hydroxide method, limestone gypsum method.
However, due to the secondary pollution of the byproducts to the environment, it has been switched to hydrogen magnesium oxide method since the 20th century; as acidic wastewater neutralizer; as the flame retardants of the synthetic resin; it was previously often used of bromine, phosphorus, chlorine and inorganic salt system. In these products, it had been mostly used of the aluminum hydroxide in these products. However, it has now been converted to magnesium hydroxide, mainly due to that in the thermoplastic resin, it can be increased of decomposition temperature to 350 ℃ or more with magnesium hydroxide; it is medically used for the control of gastric acid and laxatives; food additives, as a mineral additive, color protection agent, desiccant, alkali agent and aid of sugar production; used as a chemical reagent for measuring ammonium salt: Mg (OH) 2 + 2NH4Cl → MgCl2 + 2NH4OH.
E528 Magnesium hydroxide is an alkali that is a general purpose food additive.
E528 Magnesium hydroxide exists as a white powder and has poor solubility in water and in alcohol.
E528 Magnesium hydroxide in frozen desserts it will increase the tendency for fat globules to clump, which results in an increase in dryness.
E528 Magnesium hydroxide reacts with triglycerides in fatty acids to form soaps. it also functions as a drying agent in foods.
E528 Magnesium hydroxide is mainly used as a mild alkali, antacid, buffering agent, flame retardant, and industrial neutralizer because it releases hydroxide ions slowly due to its low solubility, allowing controlled acid neutralization without sharp pH changes.
In pharmaceutical use, E528 Magnesium hydroxide is used as an antacid to neutralize excess stomach acid and as a mild laxative that helps relieve constipation by drawing water into the intestines.
This improves digestive comfort and acid balance regulation.
In wastewater treatment, it is used to neutralize acidic water and stabilize pH levels in treatment systems without causing sudden chemical shocks to biological processes.
E528 Magnesium hydroxide improves water treatment stability and environmental safety.
In flue gas treatment, it is used to remove acidic gases such as sulfur dioxide from industrial emissions by converting them into stable magnesium salts.
This improves air pollution control and emission reduction.
In plastic and polymer manufacturing, it is used as a halogen-free flame retardant that releases water vapor when heated, helping to slow combustion and reduce smoke formation.
E528 Magnesium hydroxide improves fire safety and material performance.
In environmental remediation, it is used to treat acidic soils and contaminated water systems by gradually raising pH and helping immobilize toxic metals.
E528 Magnesium hydroxide improves soil recovery and pollution control.
In chemical manufacturing, it is used as a precursor for producing magnesium oxide and other magnesium compounds used in ceramics, refractories, and specialty chemicals.
E528 Magnesium hydroxide improves industrial chemical production efficiency.
In food processing (regulated use), E528 Magnesium hydroxide is used as a limited acidity regulator and processing aid to help control pH in certain applications.
E528 Magnesium hydroxide improves controlled food processing stability.
In laboratory chemistry, E528 Magnesium hydroxide is used in buffer systems and acid-base experiments because of its predictable, mild alkaline behavior and low solubility.
E528 Magnesium hydroxide improves experimental accuracy and chemical education.
Safety Profile Of E528 Magnesium hydroxide:
Moderately toxic by intraperitoneal route.
Human systemic effects: chlorine level changes, coma, somnolence.
Incompatible with maleic anhydride, phosphorus.
E528 Magnesium hydroxide is considered a low-to-moderate hazard substance, and compared with stronger hydroxides it is relatively safe due to its low solubility and slow release of alkaline ions, but it can still cause irritation and discomfort under certain exposure conditions.
Its risks are generally mild and manageable with standard precautions.
E528 Magnesium hydroxide improves safe handling and industrial usability.
The most common hazard is eye and skin irritation, where direct contact with powder or concentrated suspensions may cause redness, dryness, or mild burning sensations, especially with prolonged exposure or sensitive skin.
Eye contact may cause temporary irritation requiring rinsing.
E528 Magnesium hydroxide makes protective handling still necessary.
Inhalation of dust may cause respiratory irritation, including coughing, throat dryness, or discomfort, particularly in industrial environments where fine particles may become airborne during handling or processing.
Long-term exposure may increase irritation sensitivity.
This requires dust control measures.
Ingestion of large amounts may cause gastrointestinal disturbance, including nausea or laxative effects, because of its antacid and osmotic activity in the digestive system.
In normal regulated medical use, these effects are controlled and intentional.
E528 Magnesium hydroxide does not react violently under normal conditions, but it can still slowly react with carbon dioxide in air, forming magnesium carbonate over time, which slightly changes its chemical composition but does not create major safety hazards.
