Oleth-9 (inci)

Oleth(e) are the polyoxyethylene ethers of oleic acid (for comparison see: laurethe as polyoxyethylene ether of lauryl alcohol; steareth as polyoxyethylene ether of stearyl alcohol and others). In the name of the olethe, the inserted numbering means the average number of ethylene oxide units per mole. Oleth-9 is the INCI designation for a polyoxyethylene ether with 9 ethylene oxide units per mole.

Oleth-9 is used in cosmetic formulations. The polyoxyethylene ether acts as an emulsifier (changes the interfacial tension of liquids like water and oil so that they can be mixed together).