When customers describe moisturizers that "sit on top of the skin" or "feel like a mask," they're usually dealing with formulations heavy in long-chain fatty acids and occlusive agents. These products create a film on the skin's surface that technically prevents transepidermal water loss—but they accomplish this by creating a physical barrier rather than actually integrating with the skin's own lipid structure.
This is why ingredient choice matters beyond immediate results. The exfoliant that makes skin look smooth today while gradually depleting barrier function produces different long-term outcomes than the exfoliant that makes skin look smooth while actively supporting barrier health.