Glycerol monostearate is a chemical compound, glycerol ester of stearic acid, a lipid.

The name defines the structure of the molecule

• "Glycerol". It's a simple organic compound with the formula C₃H₈O₃. It is a viscous, colorless liquid, odorless, and sweet-tasting. It's widely used in food and beverages, cosmetics, and pharmaceuticals as a humectant and sweetener.
• "Monostearate". Indicates the presence of a single ester formed from stearic acid. Stearic acid is a saturated fatty acid with 18 carbon atoms.

Description of the raw materials used in its production:

• Glycerol (or Glycerin) - A trivalent organic compound, typically a byproduct of biodiesel or soap production.
• Stearic Acid - A long-chain saturated fatty acid found in many animal and vegetable oils and fats.

Industrial chemical synthesis of Glycerol Monostearate, step by step:

• Esterification - Glycerol is reacted with stearic acid in the presence of an acid catalyst (e.g., sulfuric acid) to form glycerol monostearate.
• Neutralization - If an acid catalyst is used, the reaction mixture is then neutralized with a base (e.g., sodium hydroxide).
• Separation and Purification - The formed glycerol monostearate is separated from other products and impurities by filtration or centrifugation.
• Crystallization - The glycerol monostearate is then crystallized by cooling the mixture.
• Isolation - The crystallized product is isolated through filtration.

It appears in the form of a white powder.

Pharmaceutical 

Due to its good biocompatibility and safety, is widely used as an emulsifier in pharmaceutical preparations.

Food

It is used by the food industry as an emulsifier.

Organogels or oleogels are a new class of structured lipids formed from liquid oil as a continuous phase trapped within a network of structuring molecules. The purpose of this study was to understand the role of oils with different compositions on the formation of the glycerol monostearate gel network that offer the opportunity to design food products with improved technological and nutritional properties (1).

Medical

This study demonstrated the potential applications of solid lipid nanoparticles in the delivery of lipophilic bioactive compounds in foods and other products. A new class of solid lipid nanoparticles was investigated using mixtures of propylene glycol monopalmitate (PGMP) and glycerol monostearate (GMS) and carvacrol as a lipophilic antimicrobial template (2).

Cosmetics

Skin conditioning agent - Emollient. Emollients have the characteristic of enhancing the skin barrier through a source of exogenous lipids that adhere to the skin, improving barrier properties by filling gaps in intercorneocyte clusters to improve hydration while protecting against inflammation. In practice, they have the ability to create a barrier that prevents transepidermal water loss.  Emollients are described as degreasing or refreshing additives that improve the lipid content of the upper layers of the skin by preventing degreasing and drying of the skin. The problem with emollients is that many have a strong lipophilic character and are identified as occlusive ingredients; they are oily and fatty materials that remain on the skin surface and reduce transepidermal water loss. In cosmetics, emollients and moisturisers are often considered synonymous with humectants and occlusives.

Surfactant - Emulsifying agent. Emulsions are thermodynamically unstable and are used to soothe or soften the skin and emulsify, so they need a specific, stabilising ingredient. This ingredient forms a film, lowers the surface tension and makes two immiscible liquids miscible. A very important factor affecting the stability of the emulsion is the amount of the emulsifying agent. Emulsifiers have the property of reducing the oil/water or water/oil interfacial tension, improving the stability of the emulsion and also directly influencing the stability, sensory properties and surface tension of sunscreens by modulating the filmometric performance.

Safety

Product generally considered safe.

Commercial applications 

Emulsifier in Cosmetic Products. Glycerol Monostearate is used in creams and lotions to help mix water and oils, creating a uniform texture.

Thickening Agent. It is used to increase the viscosity of cosmetic and food products.

Formula Stabilizer. It serves to stabilize the formula of skin and hair care products.

Ingredient in Food Products. Used as an emulsifier and anti-caking agent in food products.

Lubricant in Industrial Products. It is used as a lubricant in industrial applications, such as in the production of fibers and textiles.

Pearling Agent. Used in shampoos and body cleansers to give a pearlescent texture to the product.

Glycerol monostearate studies

• Molecular Formula: C₂₁H₄₂O₄
• Molecular Weight: 358.6 g/mol
• CAS: 31566-31-1    621-61-4
• UNII 230OU9XXE4
• EC Number: 204-664-4     500-265-7     250-705-4     609-412-0     238-880-5     245-121-1
• DSSTox Substance ID: DTXSID7027968     DTXSID7029160
• NSC  3875
• FEMA  2527
• Beilstein/REAXYS Number:  1799576
• MDL number  MFCD00036186
• PubChem Substance ID    329755353
• NACRES  NA.24

Synonyms: 

• Octadecanoic acid 2-hydroxy-1-(hydroxymethyl)ethyl ester
• 2-Monostearoylglycerol
• 2-Stearoylglycerol
• 2-Octadecanoylglycerol
• Glycerol β-monostearate
• β-Monostearin

References_____________________________________________________________________

(1) Ferro AC, Okuro PK, Badan AP, Cunha RL. Role of the oil on glyceryl monostearate based oleogels. Food Res Int. 2019 Jun;120:610-619. doi: 10.1016/j.foodres.2018.11.013. 

(2) He J, Huang S, Sun X, Han L, Chang C, Zhang W, Zhong Q. Carvacrol Loaded Solid Lipid Nanoparticles of Propylene Glycol Monopalmitate and Glyceryl Monostearate: Preparation, Characterization, and Synergistic Antimicrobial Activity. Nanomaterials (Basel). 2019 Aug 14;9(8):1162. doi: 10.3390/nano9081162. 

Abstract. To develop solid lipid nanoparticles (SLNs) with stable lipid matrix structures for the delivery of bioactive compounds, a new class of SLNs was studied using propylene glycol monopalmitate (PGMP) and glyceryl monostearate (GMS) mixtures and carvacrol as a model lipophilic antimicrobial. Stable SLNs were fabricated at PGMP:GMS mass ratios of 2:1 and 1:1, and the carvacrol loading was up to 30% of lipids with >98% encapsulation efficiency and absence of visual instability. Fluorescence spectra and release profiles indicated the carvacrol was successfully encapsulated and homogeneously distributed within the SLNs. SLNs fabricated with equal masses of PGMP and GMS had better stability of carvacrol during storage and higher sphericity than those with a ratio of 2:1 and were much more effective than free carvacrol against Escherichia coli O157:H7 and Staphylococcus aureus. These findings demonstrated the potential applications of the studied SLNs in delivering lipophilic bioactive compounds in food and other products.