“The term ‘skin barrier’ refers to our outermost layer of skin called the stratum corneum,” explains Gina. “The stratum corneum’s job is to protect our skin from environmental stressors, free radical damage, toxins, and pathogens (just to name a few).”
The skin barrier also contains the layers listed below in outermost to innermost order:
The acid mantle is often considered our chemical line of defense, and the lipid barrier is our physical line of defense. That’s because in the former, sebum plus amino acids help keep the pH on the acidic side to kill pathogens. The latter is mostly made of cholesterol, fatty acids, and ceramides that help keep water and moisture in and pathogens out.
For the purposes of the rest of the piece, we will be referring to all four of those layers when we say skin barrier.
