The Molecular Architecture of Free Fatty Acids: Biological Cascades, Lamellar Assembly, and Clinical Evidence in Skin Barrier Repair In the world of modern skincare, oils and fats have historically suffered from a severe identity crisis. For decades, consumer marketing divided the beauty landscape into rigid opposing camps: oil-free purists on one side, and heavy slugging enthusiasts on the other. Yet for anyone studying the biophysics of the skin barrier, this dichotomy is c