How do lipids in skin cleansers improve skin hydration?

Lipids in skin cleansers help to prevent moisture loss during and after washing. First, even after rinsing, some of the lipids remain on the skin, replenishing those that are lost during cleansing. Second, by including lipids within the formulation, the cleanser is less likely to extract natural lipids found in the skin, preserving skin's own moisture by keeping the surface layer intact.