If you formulate solid shampoo bars, two ingredients appear again and again: Sodium Lauryl Sulfoacetate (SLSA) and Sodium Cocoyl Isethionate (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, creamy lather, while SLSA is often …