Nonoxynol-50 is a nonylphenol ethoxylate derivative. Nonylphenol ethoxylates represent a group of synthetic, non-ionic surfactants derived from nonylphenols. They differ from one another in the number of hydrophilic ethoxy units of the polyethylene glycol side chain. The number of ethoxy units is given in the name e.g. Nonoxynol-50 with 50 ethoxy units.
Nonoxynol-50 is used in cosmetic formulations. The substance acts as surfactant (washing-active substance) and skin cleansing agent.