PEG-8 Distearate is a polyethylene glycol derivative used primarily as an emulsifying agent in cosmetic formulations. It helps in blending oil and water-based ingredients, enhancing the texture and stability of the product. It is commonly used in creams, lotions, and other personal care products to improve their consistency and application.

Chemical Composition and Structure:

Chemical Name: PEG-8 Distearate
Chemical Formula: (C18H35O2)2.C2H4O)n
Structure: PEG-8 Distearate consists of polyethylene glycol (PEG) chains linked to two stearic acid molecules. The structure includes a long hydrocarbon chain from the stearic acid and the polyethylene glycol backbone, which helps in emulsification and stabilization.

Physical Properties:

Appearance: White to off-white waxy solid
Odor: Mild or neutral
Melting Point: Approximately 45-50°C (113-122°F)
Boiling Point: Not applicable (decomposes before boiling)
Solubility: Soluble in oils and solvents; dispersible in water

Production Process:

Synthesis:
PEG-8 Distearate is synthesized by esterifying stearic acid with polyethylene glycol. The reaction involves heating and mixing to achieve the desired molecular weight and consistency.
Purification:
The compound undergoes purification to remove any residual reactants, unreacted stearic acid, and other impurities to meet cosmetic-grade standards.
Formulation:
It is incorporated into various cosmetic formulations, where it acts as an emulsifier and stabilizer, improving the texture and consistency of the product.

Applications:

Cosmetics: Used as an emulsifier in creams, lotions, and other personal care products to enhance texture and stability.
Personal Care: Helps in forming stable emulsions and improving the application properties of cosmetic products.

Environmental and Safety Considerations:

PEG-8 Distearate is generally regarded as safe for use in cosmetic products when used within recommended concentrations. It is important to follow established guidelines to avoid potential skin irritation or allergic reactions. Proper handling and storage are necessary to minimize environmental impact and ensure safety.

Cosmetic Safety

PEG (Polyethylene glycol) polymerize condensed ethylene oxide and water and are referred to as polyethylene glycols, but they are actually complex chemical components, polymers bonded together. For example, plastic is polyethylene and has a hard consistency, while polyethylene aggregated with glycol forms a liquid. PEGylation is produced not only as heterification but also as transesterification, which is the transformation of an alcohol by an ester.
The number that appears after the abbreviation PEG represents the molecular weight, and the higher this number is, the less it penetrates the skin.
The term 'eth' refers to the ethoxylation reaction with ethylene oxide after which residues of ethylene oxide and 1,4-dioxane, chemical compounds considered carcinogenic, may remain. The degree of safety therefore depends on the degree of purity of the compound obtained. No manufacturer appears to provide this information on the label, at least as of the date of this review.
Kim MC, Park SY, Kwon SY, Kim YK, Kim YI, Seo YS, Cho SM, Shin EC, Mok JH, Lee YB. Application of Static Headspace GC-MS Method for Selective 1,4-Dioxane Detection in Food Additives. Foods. 2023 Sep 2;12(17):3299. doi: 10.3390/foods12173299.
Abstract. "Efficient detection methods must be developed for 1,4-dioxane due to its suspected status as a human carcinogen, which is highly mobile in food and environmental resources. In this regard, this experiment has been conducted to develop reliable and selective detection and measurement methods by using static headspace (SH) isolation, followed by gas chromatography-mass spectrometry (GC-MS). A new method was developed for determining the spiked 1,4-dioxane contents in a polyethylene glycol 600 (PEG 600). The optimal condition for SH-GC-MS was discussed. The representative ions of 1,4-dioxane and 1,4-dioxane-d8 in the SIM mode of MS are 88 and 96, respectively, and the peaks of the SIM mode were separated and confirmed. The linear range for the method covers 0.25 to 100 mg/L with a coefficient of determination (R2) ≥ 0.999. The method applicability was demonstrated by spike recovery across a variety of food additives (i.e., chlorine bitartrate, choline chloride, polysorbate 20 and 60, and PEG 1000). All spike recovery from the tested samples was in the range of 89.50-102.68% with a precision of 0.44-11.22%. These findings suggest a new analytical method for food safety inspection, and could be applicable for ensuring the safety of foods and environmental and public health on a broad scale."

INCI Functions:


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.
Synonyms:

CAS: 2595268