Science
Mechanism of Action
On the skin, PEG-5 Hydrogenated Castor Oil Isostearate operates as a surfactant, effectively reducing the interfacial tension between incompatible substances like fats and water, thereby creating stable emulsions. It also serves as a potent solubilizer, enabling the uniform dispersion of ingredients such as fragrance oils, active compounds, and colorants within a formulation. Beyond its role in formulation stability, it contributes directly to skin health by forming a protective emollient film that minimizes moisture loss and significantly boosts water retention. It further aids in cleansing by facilitating the removal of dirt and oil, supports the skin's natural oil-water balance, and may assist in barrier repair with noted anti-inflammatory properties.
Research
Clinical Evidence
High confidenceN/A
Key findings
- 01 Sensitization studies by the CIR Expert Panel found PEG Hydrogenated Castor Oils safe for use at concentrations up to 100%.
- 02 Earlier safety assessments deemed PEG castor oils safe up to a 50% use concentration. For leave-on products, no specific limit is currently specified, as usage typically remains below 50% and products are formulated to be non-irritating.
Transparency
Dusting Analysis
The Formula
Formulation
Stability
This ingredient exhibits general stability but is susceptible to hydrolysis under strong acidic or alkaline conditions. It should also be protected from strong oxidizing agents. For optimal integration, it can be incorporated into the oil phase (e.g., in a 3:1 ratio to oil for related PEGs) and heated to 70-75°C, followed by the gradual addition of the water phase with continuous stirring to form a stable emulsion. Increasing its concentration may improve transparency in final products.
Conflicts
- strong acids
- strong alkalis
- strong oxidants
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has concluded that PEGylated oils, including PEG-5 Hydrogenated Castor Oil Isostearate, are safe for cosmetic application under current usage practices, provided they are formulated to be non-irritating. Dermal and ocular irritation studies involving related PEG Castor Oil ingredients observed no irritation. While trace levels of 1,4-dioxane, a manufacturing byproduct, can be a concern, purification steps effectively control its presence. PEGs are FDA-approved for general use, though caution is advised on broken skin. This ingredient is also permissible under the European Union's Cosmetics Regulation.
Your Skin
Skin Compatibility
Our Assessment
Verdict
This versatile PEGylated ingredient is a valuable formulation aid, enhancing product stability, solubilizing other components, and offering direct skin benefits like hydration, all with a well-established low safety risk.
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