Science
Mechanism of Action
This ingredient operates as an amphiphilic surfactant, lowering surface tension to effectively mix water with lipophilic substances such as oils and debris, which significantly aids in cleansing both skin and hair. Its role as an emulsifier is to stabilize oil-in-water or water-in-oil formulations by enabling the creation of finely dispersed, consistent mixtures. The polyethylene glycol (PEG) portion of its structure also acts as a humectant, forming hydrogen bonds with water molecules to attract and retain moisture within the skin, thereby providing hydration and mitigating water evaporation.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
The hydrophilic PEG2 spacer grants this ingredient free solubility in water, while its stearic acid component as an amphiphilic surfactant also confers oil-soluble characteristics. The carboxylic acid group is chemically reactive and can form stable amide bonds with primary amine groups, typically in the presence of activators such as carbodiimides or HATU. While certain PEG conjugates may exhibit pH-sensitive stability, specific optimal pH range for PEG-2 Stearamide Carboxylic Acid's stability is not detailed.
Conflicts
- Amine-containing moieties in the presence of activators (carbodiimides or HATU)
Safety
Safety Profile
The CIR Expert Panel has concluded that alkoxylated fatty amides, a class encompassing PEG-2 Stearamide Carboxylic Acid, are safe for use in cosmetics under current practices and concentrations, provided they are formulated to be non-irritating. Related PEG Stearates have shown to be non-irritating and non-sensitizing at concentrations of 25% or higher, and elicited minimal skin irritation even at 100%. While a specific SCCS opinion is unavailable, the FDA considers a related ingredient, PEG-9 Stearamide Carboxylic Acid, safe for general or limited food use. It is important to note that PEGs in general may carry potential concerns regarding contamination with toxic impurities like ethylene oxide and 1,4-dioxane.
Your Skin
Skin Compatibility
Our Assessment
Verdict
PEG-2 Stearamide Carboxylic Acid is a valuable multi-functional ingredient, offering effective cleansing, emulsification, and hydration benefits, with a low risk of irritation or comedogenicity across various non-sensitive skin types.
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