The skin barrier is the outermost layer of your skin’s surface. It consists of dead skin cells and lipids (oils) specifically- ceramides, cholesterol and free fatty acids. The skin barrier is responsible for making sure essential water and electrolytes don’t evaporate from skin. It also serves as a protective shield against harmful microorganisms by producing antimicrobial peptides and proteins.
Also, the skin barrier helps sustain skin’s immunity, and it regulates inflammation. When the skin barrier is perturbed, the skin will be prone to dryness, irritation, infections, and other symptoms you’d attribute to having sensitive skin.