Science
Mechanism of Action
As an ethoxylated glycerin, Glycereth-18 operates by attracting water molecules from both the surrounding environment and the deeper epidermal layers. This process effectively increases the water content within the stratum corneum, promoting enhanced skin moisturization and maintaining the integrity of the skin's barrier function. Its slightly viscous, water-miscible liquid form also improves product spreadability and ensures formula stability by retaining moisture within the cosmetic product itself.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Glycereth-18, a polyethylene glycol ether of glycerin, exhibits full miscibility with water. While specific optimal pH ranges were not directly identified for Glycereth-18, data on related ethoxylated glycerin compounds, such as Glycereth-20, indicate stability across a broad pH spectrum, suggesting similar robust stability. It is noted that water solubility and hygroscopicity generally decrease in polyethylene glycols with increasing molar mass.
Synergies
- Exhibits good compatibility with cationic, nonionic, and anionic surfactants (inferred from related Glycereth-20 data).
Safety
Safety Profile
The independent Cosmetic Ingredient Review (CIR) Expert Panel concluded Glycereth-18 is safe for use in cosmetics, specifically at concentrations up to a maximum of 0.32%, as per their 2021 assessment. This positive safety conclusion was further supported by a more recent August 2025 assessment on glycerin ethoxylates, deeming them safe when formulated to be non-irritating. Earlier reports (2019/2020) had indicated insufficient data regarding sensitization potential, which subsequent updates have addressed. There is no specific SCCS opinion or direct FDA status for Glycereth-18 as a cosmetic ingredient; however, glycerin itself is GRAS for food uses.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Glycereth-18 is a valuable and well-tolerated humectant and skin-conditioning agent, enhancing hydration and product aesthetics across various cosmetic applications, deemed safe for use at concentrations up to 0.32%.
Related
Similar Ingredients
Finding similar ingredients…