Your skin barrier might be the most important factor determining whether your skincare routine actually works—yet most people have no idea what it does at the cellular level. In this episode, Dr. Elena Voss breaks down the molecular science behind barrier function, explaining exactly why a compromised barrier can increase water loss by up to 75 percent and trigger inflammation that sabotages every product you apply. If you've ever dealt with mysterious dehydration, sudden sensitivity, or skin that seems to reject everything, this deep dive into the brick-and-mortar structure of your stratum corneum will finally explain what's going wrong and how to fix it.

• The skin barrier relies on a precise one-to-one-to-one ratio of ceramides, cholesterol, and free fatty acids—even slight shifts in this lipid composition measurably compromise bar ...