What a Damaged Barrier Looks Like in Practice
Skin that stings when you apply a serum that never stung before. Redness that appears without a trigger. Moisturiser that sits on the surface and does nothing by noon. These are not signs of sensitivity as a fixed trait, they are signs that the outermost layer of skin has lost enough of its lipid matrix to stop functioning as a seal. The stratum corneum is roughly 15 to 20 cell layers thick, held together by a mix of ceramides, fatty acids, and cholesterol. When that matrix thins, from over-exfoliation, harsh surfactants, low humidity, or prolonged inflammation, water escapes faster than the skin can replace it, and irritants get in more easily than they should. The fix is not a single ingredient. It is a category of ingredients that do different things toward the same goal. Centella and panthenol cover two of the most important ones.
