Emollient

Emollients fill in the micro-spaces between corneocytes (dead skin cells) in the stratum corneum, creating a smoother surface and reducing the rough, flaky feel of dry skin. They differ from humectants (which attract water) and occlusives (which block water loss) — emollients primarily improve skin texture and flexibility. Many emollients also provide a secondary occlusive effect. Plant oils, fatty acids, and esters are the most common emollient classes in cosmetics.

• Humectant An ingredient that draws water into the skin from the environment or deeper skin layers.
• Occlusive An ingredient that forms a physical barrier on the skin surface to prevent water loss.