Monostearin
[CAS# 123-94-4]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: Monostearin
• Synonyms: alpha-Monostearin; Glycerol 1-monostearate; Octadecanoic acid 2,3-dihydroxypropyl ester; Glycerin 1-monostearate
• Molecular Formula: C₂₁H₄₂O₄
• Molecular Weight: 358.56
• CAS Registry Number: 123-94-4
• EC Number: 204-664-4
• SMILES: CCCCCCCCCCCCCCCCCC(=O)OCC(CO)O

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*
• Melting point: 78 - 81 °C (Expl.)
• Boiling point: 476.9±25.0 °C 760 mmHg (Calc.)^*, 466.4 °C (Expl.)
• Flash point: 151.9±16.7 °C (Calc.)^*
• Solubility: Soluble in hot organic solvents (Expl.)
• Index of refraction: 1.469 (Calc.)^*, 1.462 - 1.468 (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P305+P351+P338

Discovery and Applications

Monostearin, also known as glyceryl monostearate, is a monoacylglycerol composed of a glycerol backbone esterified with a single stearic acid (C₁₈) moiety. It was first identified in the early 20th century during studies of natural fats and their glyceride components. The isolation of monostearin from animal and vegetable fats allowed chemists to characterize its structure and physicochemical properties, including its amphiphilic nature, melting point, and emulsifying behavior. Its combination of a hydrophilic glycerol head and hydrophobic stearic acid tail makes it a functional surfactant and stabilizer in various formulations.

Monostearin is widely used in the food industry as an emulsifier, stabilizer, and thickening agent. It helps to blend water and oil phases in products such as margarine, chocolate, ice cream, baked goods, and confectionery, providing uniform texture and preventing separation. Its ability to form crystalline networks and improve viscosity makes it especially valuable in chocolate production, where it reduces fat bloom and enhances mouthfeel. In bakery products, monostearin contributes to dough conditioning, improving elasticity and volume while maintaining moisture retention.

In pharmaceutical and nutraceutical formulations, monostearin serves as an excipient for controlled-release matrices, ointments, and topical creams. Its amphiphilic properties allow it to stabilize emulsions and disperse hydrophobic active ingredients, enhancing bioavailability and consistency. It is also employed in lipid-based drug delivery systems, such as solid lipid nanoparticles and liposomes, due to its compatibility with biological membranes and ability to form stable lipid matrices.

Cosmetic applications of monostearin leverage its emulsifying and skin-conditioning properties. It is used in lotions, creams, and hair care products to provide smooth texture, improve spreadability, and enhance water retention. Its mild nature and compatibility with other ingredients make it suitable for formulations intended for sensitive skin or hair.

Industrial applications include its use in lubricants, plasticizers, and as a release agent in molding processes. In these contexts, monostearin improves surface properties, reduces friction, and provides stability under varying temperature conditions. Its biodegradability and low toxicity contribute to environmentally acceptable formulations compared with some synthetic alternatives.

Monostearin’s production today is primarily through esterification of glycerol with stearic acid, using either chemical or enzymatic catalysts. Refinement processes ensure purity and consistency for food, pharmaceutical, and cosmetic uses. The compound’s stability, amphiphilic structure, and multifunctional properties have made it a staple in both industrial and consumer applications for over a century. Its combination of emulsifying, stabilizing, and conditioning abilities continues to make monostearin an essential ingredient in products requiring controlled texture, improved mixing, and enhanced sensory attributes.

References

2019. Addition of glyceryl monostearate affects the crystallization behavior and polymorphism of palm stearin. Bioprocess and Biosystems Engineering, 42(12).
DOI: 10.1007/s00449-019-02251-1

2021. Glyceryl monostearate-based oleogels as a new fat substitute in meat emulsion. Meat Science, 174.
DOI: 10.1016/j.meatsci.2020.108424

2025. A comparative study between stearic acid and glycerol monostearate for the development of oleogels. Journal of Food Measurement and Characterization.
DOI: 10.1007/s11694-025-03513-1