Macrogol stearate or Polyethylene Glycol" (PEG) is a chemical compound, hydroxypolyether and an octadecanoate ester.

The name defines the structure of the molecule

• "Macrogol" is another name for "Polyethylene Glycol" (PEG). It's a polymer of the monomer ethylene oxide. The term "Macrogol" is often used in Europe, while "PEG" is more common in North America.
• "Stearate" is derived from stearic acid, a saturated fatty acid with 18 carbon atoms. "Stearate" indicates the salt or ester of stearic acid.

Description of raw materials used in production

• Stearic Acid is a saturated fatty acid that serves as the primary precursor for the production of Macrogol stearate.
• Ethylene Oxide is chemical compound used for pegylating stearic acid, introducing Macrogol groups into the molecule.

Step-by-step summary of its industrial chemical synthesis process. 

• Mixture Preparation. Stearic acid is dissolved in an appropriate solvent.
• Pegylation. Ethylene oxide is reacted with stearic acid in the presence of a catalyst, thereby introducing the Macrogol groups into the molecule.
• Purification. The product is purified to remove any impurities or undesired compounds.
• Drying. The purified Macrogol stearate is dried to remove any remaining moisture.

What it is for and where

Cosmetics

Macrogol stearate is used in cosmetics as a surfactant and emulsifier.

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.

Commercial applications 

Creams and lotions. Acts as an emulsifier, helping to mix water-based and oil-based ingredients.

Hair care products. Can be found in conditioners and hair treatments to enhance product texture and distribution.

Skin cleansing products. Used in facial and body cleansers for its ability to help solubilize oils and impurities.

Pharmaceutical products. Used as a base in ointments and creams to ensure even distribution of active ingredients.

Makeup products. Can be used in foundations and other cosmetic products to enhance texture and stability.

Molecular Formula: C₂₀H₄₀O₃

Molecular Weight: 328.5 g/mol

CAS: 9004-99-3

UNII 6YLY96TQL6    YHX98F77PB

EC Number: 203-886-9    618-405-1

DSSTox Substance ID: DTXSID5026881

MDL number  

PubChem Substance ID 

Synonyms: 

• Macrogol 2000
• Glycol stearate
• Polyoxyl 40 stearate
• 2-Hydroxyethyl stearate
• Cremophor A
• Ethylene glycol monostearate
• Polyethylene glycol monostearate
• 2-Hydroxyethyl octadecanoate