Glyceryl stearate is a chemical compound, glycerol ester of stearic acid, monoglyceric monoester obtained by the esterification of glycerine and carboxylic acids (an equivalent of a carboxylic acid and an equivalent of glycerine), in this ingredient the stearic acid.

Name breakdown and function of the components

• Glyceryl - Refers to the glycerin part of the molecule. Glycerin is a tri-valent alcohol compound derived from the saponification of oils and fats.
• Stearate - Refers to the salt or ester of stearic acid, a saturated fatty acid found in many animal and vegetable oils and fats.
• Glyceryl stearate is an ester of glycerin and stearic acid. It is known for its emulsifying capabilities and is used as an ingredient in a range of cosmetics and skin care products, where it helps provide a smooth consistency and prevent the separation of liquid and oily ingredients.

Description and function of the raw materials used in production

• Glycerin - A humectant that retains moisture and helps keep skin hydrated.
• Stearic acid - A saturated fatty acid found in many oils and fats.

Summary of the industrial synthesis process step by step

• Reaction - Glycerin reacts with stearic acid, often in the presence of a catalyst, to form the ester, glyceryl stearate.
• Purification - After the reaction, the reaction mixture undergoes purification processes to remove impurities and excess catalysts.
• Isolation - Pure glyceryl stearate is then isolated, collected, and ready for use in products.

Safety. The purity level of commercial monoglyceric monoester is about 90 per cent, and impurities include fatty acids, monoglyceric diesters, mono-, di- and tri-glycerides.

It appears in the form of a fine, white powder or in small pellets with a white to slightly yellow colour.

What it is used for and where

Food

Increases consistency in baked goods, gives uniformity to ice cream and whipped cream. Non-stick agent in baking.

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.

Moisturiser, stabiliser and emulsifier. Glyceryl stearate together with PEG-75 stearate significantly influenced the consistency and thixotropic behaviour, although to a lesser extent than methyl glucose sesquistearate (1). 

In this study on optimising the formulation of oil/water cosmetic emulsions, Glyceryl stearate was found to be the dominant co-emulsifier influencing the properties of emulsions. Interactions between Glyceryl stearate and other co-emulsifiers also significantly influenced the properties of emulsions (2).

With regard to safety, emulsifiers are considered mild irritants.

Pharmaceuticals

Solidifying agent and release control agent in pharmaceuticals

Other uses

Resins. Lubricant

Plastics. Anti-fogging and anti-static agent

Commercial applications

Cosmetic and Skincare Products: Functions as an emulsifying and stabilizing agent. Helps to form a barrier on the skin's surface, reducing water loss.

Hair Products: Can be found in conditioners and hair treatments to provide body and smoothness.

Body Products: Incorporated into lotions, creams, and body care items for its emulsifying ability and moisturizing properties.

Makeup: Used in products like foundations, eyeshadows, and lipsticks to improve the product's texture and stability.

Properties

Emulsifying: Helps to form stable emulsions of oil and water.

Skin Conditioning: Provides a smooth and soft feel to the skin.

Skin Barrier: Can help reduce water loss from the skin, keeping it moisturized.

The most relevant studies have been selected to explore this in more depth:

Glyceryl Stearate studies

Typical commercial product characteristics PEG-30 Glyceryl stearate

• Molecular Formula      C₂₁H₄₂O₄
• Linear Formula    CH₃(CH₂)₁₆COOCH₂CH(OH)CH₂OH
• Molecular Weight   358,6 g/mol
• Exact Mass     358.308319
• CAS    11099-07-3    123-94-4    31566-31-1
• UNII    258491E1RZ
• EC Number: 204-664-4    250-705-4
• DSSTox Substance ID     DTXSID7027968    DTXSID7029160
• IUPAC  2,3-dihydroxypropyl octadecanoate
• InChl=1S/C21H42O4/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-21(24)25-19-20(23)18-22/h20,22-23H,2-19H2,1H3
• InChl Key      VBICKXHEKHSIBG-UHFFFAOYSA-N
• SMILES     CCCCCCCCCCCCCCCCCC(=O)OCC(CO)O
• FEMA Number 2527
• DSSTox Substance ID: 
• MDL number  MFCD00036186
• PubChem Substance ID 24896595
• RTECS     
• NSC     3875
• JECFA     918
• NCI    C80900
• RXCUI     1311165     1427173
• Beilstein     1728685
• NACRES NA.25

Synonyms: 

• Polyethylene Glycol (30) Glyceryl Monostearate
• GMS
• 2,3-Dihydroxypropyl octadecanoate
• Tagat S
• Momostearin
• 1-Stearoyl-rac-glycerol
• Monoglyceride