Description
Magnesium lactate, with the chemical formula Mg(C₃H₅O₃)₂, is an inorganic salt derived from magnesium and lactic acid, often encountered as a dihydrate (Mg(C₃H₅O₃)₂·2H₂O) or trihydrate form. It is a white, crystalline powder that serves as a bioavailable source of magnesium, an essential mineral for bodily functions such as heart rhythm, nerve transmission, and muscle contraction.
This compound is naturally occurring in some foods but is primarily produced synthetically for use as a dietary supplement to prevent or treat magnesium deficiency, which can lead to symptoms like muscle cramps, fatigue, or irregular heartbeat.
Magnesium lactate is considered highly absorbable compared to other magnesium salts, making it suitable for oral supplementation, though it may interact with certain medications or affect nutrient absorption.
Structure
Magnesium lactate has an ionic structure, consisting of a magnesium cation (Mg²⁺) ionically bonded to two lactate anions (C₃H₅O₃⁻). The lactate ion is derived from lactic acid (CH₃CH(OH)COOH), where the carboxylate group (COO⁻) coordinates with the magnesium ion. In its crystalline form, it often includes water molecules, such as in the dihydrate, where the magnesium is octahedrally coordinated with oxygen atoms from the lactate carboxylates and water.
The overall molecular structure can be represented as Mg²⁺[CH₃CH(OH)COO⁻]₂, with the lactate ions featuring a chiral center at the carbon bearing the hydroxyl group, potentially existing as D- or L-isomers, though commercial forms are often the DL-racemic mixture.
Properties
- Physical Properties: White, odorless crystalline powder or granules with a molar mass of 202.45 g/mol (anhydrous) or 238.48 g/mol (dihydrate). It is hygroscopic and stable under normal conditions.
- Solubility: Highly soluble in water (approximately 100 g/L at 20°C), slightly soluble in alcohol, and insoluble in ether, facilitating its use in aqueous solutions.
- Melting and Boiling Points: Decomposes before melting, with a decomposition temperature around 240°C; not volatile.
- Density: Approximately 1.5–1.6 g/cm³ for the dihydrate form.
- Chemical Properties: Neutral to slightly acidic in solution (pH around 6–7), non-oxidizing, and stable in air but may degrade under high heat or strong acids/bases. It exhibits good bioavailability due to the organic lactate ligand, which aids magnesium absorption in the gut.
Preparation
Magnesium lactate is typically prepared by neutralizing lactic acid with a magnesium base:
- Reaction with Magnesium Hydroxide or Oxide: Lactic acid (C₃H₆O₃) is reacted with magnesium hydroxide (Mg(OH)₂) or magnesium oxide (MgO): 2C₃H₆O₃ + Mg(OH)₂ → Mg(C₃H₅O₃)₂ + 2H₂O or 2C₃H₆O₃ + MgO → Mg(C₃H₅O₃)₂ + H₂O. The mixture is heated, filtered to remove impurities, and crystallized from the solution, often yielding the dihydrate form.
- Reaction with Magnesium Carbonate: Magnesium carbonate (MgCO₃) can be used similarly: 2C₃H₆O₃ + MgCO₃ → Mg(C₃H₅O₃)₂ + CO₂ + H₂O. This method is common in industrial production, followed by evaporation and drying.
- Industrial Synthesis: Food-grade magnesium lactate is produced under controlled conditions to ensure purity, often involving fermentation-derived lactic acid for natural labeling.
Uses
Magnesium lactate is versatile due to its high bioavailability and mild taste:
- Dietary Supplements: Used to treat magnesium deficiency, supporting heart health, muscle function, and nerve activity; often in tablets or powders for conditions like cramps or fatigue.
- Food and Beverages: Acts as a mineral fortifier in fortified foods, beverages, and nutritional products, providing magnesium without altering flavor significantly.
- Pharmaceuticals: Incorporated in antacids, laxatives, or electrolyte solutions; may help with leg cramps or as an adjunct in migraine prevention.
- Cosmetics and Personal Care: Added to skincare products for its humectant properties and to stabilize formulations.
- Other: In animal feed as a magnesium source or in biochemical research for enzyme studies.
Additional Notes:
- Safety: Generally recognized as safe (GRAS) by regulatory bodies when used appropriately, but excessive intake can cause diarrhea or gastrointestinal upset. Consult a healthcare provider for dosage, especially with kidney issues.
- Environmental Impact: Biodegradable and non-toxic, with production often from renewable lactic acid sources.
- Storage: Store in cool, dry conditions in sealed containers to prevent moisture absorption.