SLSa is a plant derivative (coconut and palm). By its nature, hydrophilic, it is going to break up oils whether it be in the bath water or on your skin. That is one of the main characteristics of this particular surfactant. However, that being said it is probably the most skin friendly surfactant due to the size of its large molecular structure. The smaller the molecular structure, the farther it can penetrate the dermis layers.