Sodium laureth sulfate, or sodium lauryl ether sulfate (SLES), is a detergent and surfactant found in many personal care products (soaps, shampoos, toothpaste etc.). SLES is an inexpensive and very effective foaming agent.SLES, SLS, ALS and sodium pareth sulfate are surfactants that are used in many cosmetic products for their cleansing and emulsifying properties. They behave similarly to soap.