Glyceryl monostearate
[CAS 31566-31-1]

Identification

• Classification: Food additive >> Emulsifier
• Name: Glyceryl monostearate
• Synonyms: 2,3-Dihydroxypropyl octadecanoate; Monostearin; GMS
• Molecular Formula: C₂₁H₄₂O₄
• Molecular Weight: 358.56
• CAS Registry Number: 31566-31-1
• EC Number: 250-705-4
• SMILES: CCCCCCCCCCCCCCCCCC(=O)OCC(CO)O

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*
• Melting point: 55-60 °C (Expl.)
• Boiling point: 485.7±25.0 °C 760 mmHg (Calc.)^*
• Flash point: 155.6±16.7 °C (Calc.)^*
• Index of refraction: 1.469 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

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

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315

chemBlink Chemical Story

Glyceryl monostearate, also known as monostearin, is a monoacylglycerol composed of a glycerol backbone esterified with a single stearic acid (C₁₈) molecule. It was first identified in the early 20th century through studies of natural fats and the composition of triglycerides. The compound’s amphiphilic structure, featuring a hydrophilic glycerol head and a hydrophobic stearic acid tail, imparts emulsifying, stabilizing, and thickening properties that have made it a widely used additive in food, pharmaceutical, and cosmetic industries.

In the food industry, glyceryl monostearate is primarily employed as an emulsifier, helping to blend water and oil phases in products such as margarine, chocolate, ice cream, baked goods, and confectionery. Its ability to form crystalline networks enhances texture, prevents separation, and improves product consistency. In chocolate, it reduces fat bloom and contributes to a smooth mouthfeel, while in bakery products, it aids dough conditioning, moisture retention, and elasticity, resulting in improved volume and texture.

Pharmaceutical applications leverage glyceryl monostearate’s emulsifying and stabilizing abilities. It is used as an excipient in creams, ointments, and controlled-release formulations, where it stabilizes emulsions and disperses hydrophobic active ingredients. Its compatibility with lipid-based drug delivery systems, such as solid lipid nanoparticles and liposomes, facilitates enhanced bioavailability and controlled release of therapeutic agents.

Cosmetic formulations benefit from glyceryl monostearate’s skin-conditioning and emollient properties. It is included in lotions, creams, and hair care products to improve spreadability, retain moisture, and create a smooth, soft texture. The compound’s mild nature and stability make it suitable for products intended for sensitive skin or hair.

Industrial uses of glyceryl monostearate include its function as a lubricant, plasticizer, and release agent in molding processes. In these contexts, it improves surface properties, reduces friction, and provides thermal stability. Its biodegradability and low toxicity make it a favorable alternative to certain synthetic additives in environmentally sensitive applications.

The production of glyceryl monostearate today typically involves the esterification of glycerol with stearic acid using chemical or enzymatic catalysts, followed by purification to achieve consistent quality for various applications. Its combination of emulsifying, stabilizing, and conditioning functions has maintained its importance in multiple industries for over a century. The discovery and utilization of glyceryl monostearate highlight the practical value of naturally derived monoacylglycerols, providing versatile solutions for food, pharmaceutical, cosmetic, and industrial products that require controlled texture, stability, and performance.

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