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PEG-8 STEARATE.

Valuable CAS 9004-99-3 / HUMECTANT, SURFACTANT - CLEANSING, SURFACTANT - EMULSIFYING

PEG-8 Stearate is a polyoxyethylene ester of stearic acid, functioning as a multifaceted ingredient in skincare. It effectively stabilizes oil and water mixtures, gently cleanses the skin, and imparts conditioning benefits.

Emulsifying Surfactant/Cleansing Emollient Skin-conditioning Humectant

Science

This ingredient primarily acts as an emulsifier, crucially enabling the stable blend of immiscible oil and water phases within a formulation. Its surfactant properties reduce surface tension, aiding in the lifting and removal of impurities and oils from the skin. Furthermore, PEG-8 Stearate serves as a skin-conditioning agent and emollient, forming a protective film that softens and smooths the skin while helping to minimize trans-epidermal water loss. Some data also indicate its role as a humectant, capable of attracting and retaining moisture on the skin's surface.


Research

High confidence
Effective range 1–15%
Optimal

N/A


Transparency

Not commonly dusted

The provided research does not indicate that PEG-8 Stearate is commonly associated with 'dusting' or has specific concentration thresholds for adverse effects beyond general formulation practices.


The Formula

Solubility
Water
Optimal pH 6 – 7.5
0 7 14

Stability

PEG-8 Stearate exhibits optimal stability within a pH range of 6.0-7.5, with a 3% aqueous solution typically having a pH of approximately 6. It generally maintains stability in the presence of moderately strong acids, alkalis, and electrolytes. However, exposure to strong acids and bases can lead to gradual hydrolysis and saponification, affecting its integrity. This ingredient is soluble in water and organic solvents such as ethanol and chloroform, yet it remains insoluble in mineral and vegetable oils. Its molecular structure contains ether oxygens and ester bonds, which may render it vulnerable to enzymatic cleavage. It demonstrates broad compatibility with amphoteric, anionic, cationic, and nonionic surfactants, and is frequently co-formulated with fatty alcohols and acids.

Synergies

  • Amphoteric surfactants
  • Anionic surfactants
  • Cationic surfactants
  • Nonionic surfactants
  • Fatty alcohols
  • Fatty acids

Conflicts

  • Strong acids
  • Strong bases

Safety

CIR Status
Safe as used
Max tested
25%
Sensitization risk Low

The Cosmetic Ingredient Review (CIR) Expert Panel has consistently affirmed PEG-8 Stearate's safety as a cosmetic ingredient in current usage concentrations, with conclusions first published in 1983 and reaffirmed through a re-review in 2024. The U.S. FDA also permits its use in food. While clinical data support its non-irritating and non-sensitizing profile at concentrations up to 25%, a recognized concern for PEG compounds is potential contamination with impurities like ethylene oxide and 1,4-dioxane, byproducts of the ethoxylation process, if purification is inadequate. It is recommended to avoid application on damaged skin. Although generally well-tolerated, individuals with highly sensitive skin or existing allergies might still experience mild irritation or reactions.


Your Skin

Yes Normal
Yes Dry
No Oily
Yes Sensitive
Irritancy Low
Comedogenicity Medium

Our Assessment

Valuable

PEG-8 Stearate is a valuable ingredient, highly regarded for its established safety and efficacy in stabilizing formulations, enhancing skin conditioning, and contributing to gentle cleansing, making it suitable for diverse cosmetic applications.


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