If you formulate solid shampoo bars, two ingredients appear again and again: Natriumlaurylsulfoacetaat (SLSA) en natriumcocoylisethionaat (SCI). Both are anionic surfactants commonly used in solid cleansing products, and both can be used in syndet shampoo bars. But they are not interchangeable ingredients. Formulators frequently describe SCI as contributing a dense, romig schuim, while SLSA is often …