If you’ve ever watched a skincare TikTok or read a product description, chances are you’ve heard of the skin moisture barrier. But what is it? And how does it work?
Join us for a deep dive into the science behind the skin moisture barrier and learn how barrier repair is a key component to healthy, radiant skin.
What we commonly refer to as the skin moisture barrier (aka “acid mantle”) is actually a layer of actively shedding skin cells on the outermost part of the epidermis called the stratum corneum. While it’s only a few microns thick, the stratum corneum is the body’s first defense. Its function: seal in moisture and electrolytes while protecting the skin from irritants and bacteria.
The stratum corneum is made up of two layers of corneocytes, which are skin cells that have been sacrificed to shield the underlying layers. The uppermost layer of corneocytes, which is what we see in the mirror, is the loosest layer of the stratum corneum. The lower layer of corneocytes is made up of larger, more rigid cells that are more hydrophobic, meaning they repel water.
A layer of intracellular lipids acts like mortar between bricks, holding the two layers of corneocytes together to maintain the skin moisture barrier’s integrity. They also mix with sebum on the skin’s surface to form skin surface lipids (SSL).
Healthy levels of intracellular and skin surface lipids enable the skin to pull moisture from the air to rehydrate itself and prevent transepidermal water loss (TEWL).
Trans epidermal water loss (TEWL) is the scientific process that describes a damaged moisture barrier. When TEWL occurs, moisture escapes, causing the skin to become dry and irritated. That dry, tight feeling you get after using a harsh cleanser? That’s what TEWL feels like.
Other signs of a damaged moisture barrier include:
Common causes of a damaged moisture barrier include:
In other words, modern life can cause a compromised moisture barrier. But there’s good news: we can fix it.
The skin’s ability to repair itself is nothing short of remarkable. With a little help from the right skincare, you can repair your moisture barrier and restore your skin to health. To do this, you need to add moisture back into your skin, then seal it in to help restore the lipid layer and repair your skin barrier.