Magnesium sulfate heptahydrate

Synonyms: Magnesium sulfate heptahydrate, Epsom salt, Bitter salt, MgSO4·7H2O, CAS 10034-99-8

Magnesium sulfate heptahydrate is a white, water-soluble crystalline solid that has been a staple in pharmaceutical, personal care, and industrial formulations for well over a century. Its enduring popularity stems from a rare combination of high magnesium bioavailability, gentle osmotic action, and exceptional safety profile — qualities that keep it in steady demand across laxative, bath soak, and magnesium supplementation categories. In recent years, formulators have also turned to it as a magnesium source in sports recovery and wellness products, where consumer awareness of magnesium’s role in muscle function continues to rise.

Chemically, the compound consists of one magnesium cation, one sulfate anion, and seven molecules of water of crystallization. This heptahydrate form is the most common and stable hydrate under ambient conditions, with a molecular weight of 246.47 g/mol. It occurs naturally as the mineral epsomite and is produced industrially through the reaction of magnesium oxide or magnesium carbonate with sulfuric acid, followed by controlled crystallization. The sulfate component itself contributes to the compound’s osmotic and electrolyte-balancing properties, making it useful beyond magnesium delivery alone.

Commercial grades of magnesium sulfate heptahydrate are typically specified at ≥99.5% purity, with tight control on heavy metals, chloride, and iron content to meet pharmacopeial standards such as USP, BP, and EP. For buyers, the key differentiators are consistent crystal size distribution, low microbial bioburden, and reliable dissolution behavior — factors that directly affect downstream processing and end-product performance.

Product Overview & Composition

Magnesium sulfate heptahydrate is an inorganic salt with the formula MgSO4·7H2O, comprising 9.86% magnesium, 39.01% sulfate, and 51.13% water by mass. The heptahydrate lattice is built from [Mg(H2O)6]2+ octahedra linked by sulfate tetrahedra and additional water molecules via hydrogen bonding, which accounts for its well-defined crystal habit and moderate thermal stability. Upon heating, it progressively loses water, transitioning through lower hydrates before becoming anhydrous magnesium sulfate above 250°C.

The compound’s high water solubility — roughly 71 g per 100 mL at 20°C — and clear, colorless solutions make it easy to incorporate into liquid and semi-solid formulations. It is chemically inert toward most excipients, though it can form insoluble precipitates with calcium or phosphate ions under certain conditions, a consideration in multi-mineral formulations. Its neutral to slightly acidic pH in solution supports compatibility with a broad range of topical and oral delivery systems.

Key Applications

• Pharmaceutical laxatives: Acts as an osmotic laxative by drawing water into the intestinal lumen; used in oral solutions and powders.
• Magnesium supplementation: Provides highly bioavailable magnesium for dietary supplements targeting muscle, nerve, and cardiovascular health.
• Bath and spa products: Widely used in Epsom salt soaks for muscle relaxation and skin soothing, often blended with essential oils.
• Personal care: Functions as a viscosity modifier and electrolyte in toothpaste, mouthwash, and skin care emulsions.
• Sports recovery: Incorporated into post-workout baths and topical gels to support muscle recovery and electrolyte balance.
• Food processing: Used as a firming agent, flavor enhancer, and magnesium fortificant in certain food and beverage applications.

Quality & Standards

Packaging & Supply

• Packaging: 25 kg PP woven bags with PE liner, 1000 kg jumbo bags, or custom packaging upon request.
• MOQ: 1 metric ton (flexible for trial orders).
• Lead time: 3-5 business days (stock items)
• Documentation: COA, MSDS, TDS, and regulatory support available.
• Capacity: 500 metric tons per month to ensure stable supply.

Request For Quote

• LyvBio Co., Ltd. — Email: info@lyvbio.com