Science
Mechanism of Action
This ingredient functions as a lipophilic surfactant, possessing a molecular architecture with distinct hydrophilic (polyglycerol) and lipophilic (stearic acid) segments. This duality enables it to significantly reduce the interfacial tension between immiscible oil and water phases, thereby facilitating the formation and long-term stability of emulsions. Within a cosmetic matrix, it ensures homogeneity and consistent product texture. Furthermore, it imparts moisturizing and softening properties, acting as a skin conditioning agent.
Research
Clinical Evidence
Medium confidenceN/A
Key findings
- 01 Typical usage concentrations for its emulsifying and stabilizing functions in formulations range from 1% to 5%.
- 02 Concentrations between 0.5% and 0.9% were observed to enhance emulsion stability, as indicated by lower stability index values in specific dairy cream emulsion studies.
- 03 An in vitro study confirmed a concentration of 0.5% to be non-cytotoxic for Polyglyceryl fatty acid ester (PGFE)-based nanostructured lipid carriers in Caco-2 cells, suggesting good cellular compatibility.
Transparency
Dusting Analysis
The available research data does not provide information regarding 'dusting' properties or concerns for Polyglyceryl-4 Stearate.
The Formula
Formulation
Stability
As a non-ionic emulsifier, Polyglyceryl-4 Stearate demonstrates robust stability across a wider pH range compared to its ionic counterparts, although extreme pH values can still influence overall formulation integrity. It exhibits good resistance to salts and acids, contributing to stable emulsions even under challenging conditions. Thermal stability is generally favorable, with Polyglycerol fatty acid esters (PGFEs) remaining stable under neutral conditions below 100°C.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has deemed polyglyceryl fatty acid esters, including Polyglyceryl-4 Stearate, safe for use in cosmetic products under current practices and concentrations, provided formulations are non-irritating. It is well-tolerated by most skin types and is an approved cosmetic ingredient within the European Union. Its absence from the FDA's Inactive Ingredient Database indicates it is not currently used as an excipient in approved US pharmaceutical products.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Polyglyceryl-4 Stearate is a valuable ingredient for its essential role in creating stable, elegant cosmetic emulsions and providing mild skin conditioning without concerns for irritancy or comedogenicity.
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References
Sources