What it is
This ingredient is an ester of isostearic acid and a four-unit polyglycerol backbone, giving it both oil-loving and water-loving regions. In sunscreens it acts as a gentle nonionic emulsifier, stabilizing emulsions and helping disperse oils and, in mineral formulas, pigments such as titanium dioxide and zinc oxide. It also contributes a light, smooth skin feel and supports spreadability.
Safety & warnings
Polyglyceryl esters are nonionic and generally regarded as mild and well tolerated, with a low irritation profile suitable for sensitive-skin formulations.
Origin & sourcing
Synthetic, produced from polyglycerol derived from glycerin and isostearic acid, both of which can be sourced from plant or other feedstocks.
Questions everyone asks
What does polyglyceryl-4 isostearate do in a formula?
It is a mild nonionic emulsifier that blends oil and water phases and helps disperse pigments, while adding a smooth feel.
Is it a harsh surfactant?
No, polyglyceryl esters are nonionic and considered gentle, which is why they are common in mild and sensitive-skin products.