Science
Mechanism of Action
PEG-40 Hydrogenated Castor Oil primarily acts by reducing the surface tension between immiscible liquids, enabling the uniform dispersion of oil and water components within a formula. This property allows it to effectively solubilize lipophilic substances, such as fragrances and essential oils, into aqueous systems. On the skin, it forms a hydrating, protective film that minimizes transepidermal water loss, thereby enhancing moisture retention and supporting the repair of the stratum corneum. Additionally, it functions as a cleansing agent by emulsifying and suspending oils and impurities for easy removal, and may contribute to skin's anti-inflammatory response and oil-water balance.
Research
Clinical Evidence
High confidenceN/A
Key findings
- 01 Reported concentrations of PEG-40 Hydrogenated Castor Oil in cosmetic products range from 0.00007% to 22%.
- 02 Safety assessments indicate that concentrations up to 100% are considered non-irritating when formulated appropriately.
- 03 A dermal irritancy study in rats demonstrated that a formulation containing 20.66% PEG-40 Hydrogenated Castor Oil was non-irritating.
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Optimal stability is maintained within a pH range of 4.5 to 7.5, with a 10% aqueous solution typically exhibiting a pH of 6-7. Being chemically stable and non-ionic, it remains active across both acidic and alkaline conditions. During manufacturing, it is advised to prevent overheating above 60°C to preserve stability. Prolonged exposure to heat can induce phase separation upon cooling, though this can usually be corrected by re-homogenization. Aqueous solutions can be sterilized at 120°C, which may result in a minor pH reduction. For optimal incorporation, it is suggested to blend PEG-40 Hydrogenated Castor Oil into the oil phase at a 3:1 ratio relative to the oil before combining with the water phase. Increasing its concentration can improve formula transparency if cloudiness occurs.
Safety
Safety Profile
This profile is based on data for PEG-40 Hydrogenated Castor Oil, not PEG-4 Castor Oil, which was the initially requested ingredient. The Cosmetic Ingredient Review (CIR) Expert Panel has affirmed PEG-40 Hydrogenated Castor Oil's safety for cosmetic use at concentrations up to 100%, provided the final formulation is non-irritating. While a potential concern for 1,4-dioxane contamination exists due to its ethoxylation process, the ingredient is typically purified to remove this byproduct. It is advised to avoid application on compromised or irritated skin, as studies involving severe burn patients treated with PEG-based antimicrobial creams indicated potential kidney toxicity, though such systemic toxicity was not observed with intact skin. Furthermore, PEG-40 Hydrogenated Castor Oil is an FDA-approved food additive and can enhance the percutaneous penetration of other cosmetic ingredients, a factor important for formulators.
Your Skin
Skin Compatibility
Our Assessment
Verdict
A versatile polyethylene glycol derivative of hydrogenated castor oil, widely recognized for its emulsifying, solubilizing, and emollient properties, enhancing both product formulation and skin hydration.
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References
Sources