Science
Mechanism of Action
As a positively charged quaternary ammonium compound, Quaternium-18 electrostatically binds to the negatively charged surfaces of skin and hair, delivering conditioning benefits. It functions as a mild surfactant for cleansing and acts as an emulsifier to stabilize immiscible oil and water phases. Its derivatives, specifically Quaternium-18 Bentonite and Quaternium-18 Hectorite, further contribute to formulation integrity by dispersing insoluble solids and controlling product viscosity.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Quaternium-18 clays, such as Quaternium-18 Hectorite and Bentonite, exhibit exceptional heat stability up to 500°C and maintain integrity against acid or base attacks within a broad pH range of 3-11.
Conflicts
- Banned in certified organic cosmetics due to environmental toxicity and poor biodegradability.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel consistently affirmed Quaternium-18 and its derivatives as safe for cosmetic use, with reaffirmations in 2001 and 2019/2020. Studies indicate poor skin absorption and minimal systemic effects from acute oral and percutaneous exposure. In humans, it demonstrated practically nonirritating and nonsensitizing properties. The FDA recognizes bentonite, a component of Quaternium-18 Bentonite, as Generally Recognized as Safe (GRAS) for direct food use. European applications are subject to compliance with EU regulations concerning animal by-products.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Quaternium-18 is a valuable multi-functional ingredient for conditioning, emulsification, and stability in skin and hair care, boasting a strong safety profile at concentrations up to 0.95%, though its environmental impact precludes its use in certified organic formulations.
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References
Sources