1. A substance that works alongside a primary surfactant to enhance the stability, solubility, or effectiveness of a solution or emulsion.
Usage: technical; chemistry; commonly used in pharmaceutical and cosmetic formulations

Examples

• The formulation included a cosurfactant to improve the stability of the oil-in-water emulsion.
• Cosurfactants are often added to microemulsion systems to reduce interfacial tension.
• In cosmetic products, a cosurfactant helps maintain the consistency and shelf life of the preparation.
• The pharmaceutical company selected a cosurfactant that would enhance drug solubility without irritating the skin.
• Alcohols and polyols are commonly used as cosurfactants in detergent formulations.