Science
Mechanism of Action
This ingredient primarily functions as a non-ionic surfactant, adept at reducing the surface tension of cosmetic formulations, which facilitates even product distribution and aids in gentle cleansing by lifting impurities. As an emulsifier, it stabilizes oil-in-water emulsions by effectively solubilizing lipophilic components such as oils, fragrances, and active ingredients within aqueous systems. Additionally, it offers mild emolliency to the skin, helping to soften and soothe by forming a protective film that diminishes moisture loss and promotes sustained skin hydration.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
A 1% aqueous solution of PEG-35 Hydrogenated Castor Oil maintains a pH between 5.0 and 8.0. It forms clear solutions in water and is also soluble in various organic solvents, including ethyl alcohol and chloroform. Its solubility in water decreases with rising temperature, potentially leading to turbidity. The ingredient can be sterilized by autoclaving at 120°C for 30 minutes, although this may cause a slight deepening in shade. It exhibits stability towards electrolytes in aqueous solutions, provided concentrations are not excessively high. However, it is incompatible with strong acids or alkalis during sterilization due to the risk of saponification, and certain phenolic compounds like phenol or resorcinol may cause precipitation at specific concentrations. It is particularly effective at solubilizing essential oils and aroma chemicals in aqueous-alcoholic solutions (30-50% alcohol).
Synergies
- enhanced solubilization of essential oils and aroma chemicals in aqueous-alcoholic solutions (30-50% alcohol)
Conflicts
- strong acids during sterilization
- strong alkalis during sterilization
- some organic substances containing phenolic hydroxyl groups (e.g., phenol, resorcinol, tannin) at specific concentrations
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel determined that related compounds, PEG-30 and PEG-40 Hydrogenated Castor Oil, are safe for use in cosmetics at concentrations up to 100%. While a specific maximum concentration for PEG-35 Hydrogenated Castor Oil is not explicitly defined, these findings suggest a high tolerance. The Environmental Working Group (EWG) assigns a low to moderate hazard rating primarily due to the potential for 1,4-dioxane contamination, a byproduct of the ethoxylation process, which is minimized in purified grades. At typical use levels (1-10%), it demonstrates low irritation and sensitization potential. However, it can increase the sensitization potential of other ingredients. Products containing PEGs are generally advised against use on broken or irritated skin due to their role as penetration enhancers and the potential for impurities. The FDA lists castor oil as a flavoring agent, and PEG Castor Oil derivatives are approved as indirect or direct food additives.
Your Skin
Skin Compatibility
Our Assessment
Verdict
PEG-35 Hydrogenated Castor Oil is a valuable multi-functional ingredient for formulation, serving as an effective emulsifier, solubilizer, and mild emollient, generally well-tolerated on normal skin, though caution is advised on compromised barriers.
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