Home Skincare Glossary Moisture Barrier Moisture barrier, also known as the skin barrier or lipid barrier, refers to the outermost layer of the skin, known as the stratum corneum, and the protective barrier it forms to maintain hydration and protect the skin from external aggressors. 8 Best Skin Barrier Repair Creams for a Healthy, Hydrated Glow Our Top 5 Favorite Lightweight Moisturizers for the Summer 2024 Top 10 Best Moisturizers for Winter