What is the Skin Barrier? How to Repair and Maintain It

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Think of your skin barrier as your first and best line of defense against outside aggressors, be it bacteria or pollution. Keeping it strong and healthy is key for radiant skin, which is why it’s essential to both address and prevent damage. Here, how best to care for your skin barrier.

What is the skin barrier?

The skin barrier is a scientific term for the outermost layer of your skin, responsible for keeping moisture in and damaging elements (like UV and free radicals) out. When the barrier function is working well, skin is hydrated, plump, and firm. But when it breaks down, overall skin health goes with it.

That’s because the barrier, or stratum corneum, is what stands between us and the outside world, preventing environmental chemicals and biological irritants from entering skin, including free radicals, bacteria, other microbes, allergens, toxic chemicals, ultraviolet light, injury and other external assaults. So the key to skin health — and radiance — is a vital barrier function. 

But that’s not all. It turns out that the barrier’s most important task is to prevent the escape of water from inside the body. The outermost layer of skin “is made up of multiple stacks of flattened cells or ‘corneocytes,’ each of which is encased in a thick coating of fat (or ‘lipid’),” according to UCSF dermatologists Peter M. Elias and Mary L. Williams. 

Likening the stratum corneum to a brick wall, the stacks of cells are bricks and the fatty matrix surrounding them the mortar. Together they form a barrier that keeps skin’s precious water content inside, so skin stays firm, hydrated, and less prone to wrinkles.

How Do I Know If My Skin Barrier is Damaged?

Dry, flaky, itchy, irritated or sensitive skin are all common signs of a damaged or weakened barrier function. For despite all the heavy lifting it does, the barrier is delicate and prone to thinning with age. In fact, any assault on the stratum corneum — either from external damage or as a result of cellular water loss — can lead to sensitized and dehydrated skin that is susceptible to environmental harm, dryness, irritation, breakouts, sagging skin and other signs of aging.

Appearance, however, is just one reason to maintain a healthy skin barrier. Damaged lipids in the mortar — from harsh detergents, physical harm to the skin, or environmental stress — cause the skin to lose water and dry out. And when skin is dry, it’s more permeable to irritants and allergens that trigger inflammation, which can lead to a host of issues, including rosacea, acne, eczema, and premature aging, among other things. 

Maintaining the integrity of the protective barrier, then, is the secret to healthy, radiant skin. Take these steps to ensure the health of your barrier function:

  • Minimize sun exposure by wearing hats and non-nano zinc oxide sunscreen. 
  • Avoid other outside-in attacks on the skin, including overzealous exfoliation, harsh soaps, chemicals and other pollutants
  • Support barrier function health with nourishing oils and strengthening serums. 

How do I repair my skin barrier?

1. Cleanse with Gentle Cleanser

Cleansing overzealously — or with harsh, drying ingredients — could interfere with the integrity of your skin barrier. Opt for gentle ingredients that melt away makeup and impurities without rubbing or scrubbing.

2. Heal with Antioxidants

While you may know and love antioxidants for their ability to keep free radicals from destroying collagen, they’re essential for maintaining the skin barrier, too — since free radicals also damage the outer skin barrier in their frenzy. Plus, a study found that antioxidants can actually work within the skin barrier to keep it healthy when it’s under stress. Try adding the Antioxidant Booster to your serum for extra barrier protection.

3. Hydrate Your Skin

The skin barrier is commonly referred to as the moisture barrier, and for good reason: Moisturizing molecules, such as lipids, help lock hydration within the skin. So it’s helpful to replenish that all-important “mortar” that makes up the barrier. The combination of antioxidant-rich plant oils and soothing helichrysum in Calm Pure Radiance Oil does just that.

4. Exfoliate Correctly

Exfoliation is one of the major contributors to a damaged skin barrier. Still, few things are better for radiant, healthy skin — you need to slough away dead skin cells, after all — so it’s important to do so properly. Consider using lactic acid, beloved by aestheticians for all skin types, and keeping an eye out for signs of over-exfoliation.

5. Moisturize Well

Your skin loses more moisture while you sleep than it does during the day, so it’s important to keep skin well-hydrated in the overnight hours. The Moisture Lock Overnight Mask delivers hyaluronic acid for instant hydration as well as a squalene and mango butter to fortify the barrier, thus sealing it in.

6. Use Sunscreen

Not only does UV light damage skin and contribute to skin cancer, but it can also sap moisture from your skin barrier, ultimately compromising its proper function. Consider this yet another reason to make sunscreen a non-negotiable in your daily routine. The payoff is well worth the extra step.

What are the best hydrators for your skin barrier?

Whether skin is one week or 100 years old, the idea is the same: hydrated skin is resilient skin. And although we have to work harder as we age to maintain cellular hydration, moisture loss can be checked with the help of botanical oils that are high in essential fatty acids (EFAs)—including algae, passion fruit, baobab, and kiwi seed oils—which penetrate deep within the cells to bolster the body’s own moisturizing agents.

These antioxidant-rich oils work best in conjunction with molecules and other compounds designed to further support the health of your skin’s protective barrier. Here are three key ingredients to look for:

Hyaluronic Acid

Keep an eye out for products that contain hyaluronic acid, a naturally-occurring molecule that helps maintain skin’s moisture. Hyaluronic acid is “a natural sugar in the skin that sits between skin cells and helps maintain hydration and skin plumpness,” Josh Zeichner, M.D., director of cosmetic and clinical research in dermatology at New York’s Mt. Sinai Hospital, told Elle magazine. Its humectant properties enable it to hold onto “moisture by pulling in water to the skin like a sponge. As time goes on, the level of naturally occurring hyaluronic acid decreases—that’s why people’s skin gets [drier] and sags as they get older. Adding it to your skin care regimen counteracts that fate.


You’ll also want to further support the health of your skin barrier by adding peptides to your skincare routine. Peptides are compounds that communicate a message to your skin that it has lost collagen and needs to manufacture more; in essence, topical application tricks the body into generating new collagen. The results of a study published in Skin Research and Technology on the effect of peptides administered to skin demonstrate that “treated areas show[ed] an increase in hydration and elasticity as a result of keratin peptide application.” They also “indicate that the keratin formulations reinforce the skin barrier integrity, improving its water-holding capacity.” Yet another report, this one in the International Journal of Tissue Reactions, establishes that the “application of the collagen-like peptide on the skin significantly reduced the total surface of wrinkles.” Researchers also note a “decrease in number and average depth of wrinkles.”


Then there are ceramides, waxy, fatty molecules found in skin that hold it together and help prevent moisture loss. (You can think of ceramides as the mortar surrounding the cellular bricks.) While young skin features ceramides in abundance, older skin manufactures far less. According to a review published in the American Journal of Clinical Dermatology, “most skin disorders that have a diminished barrier function present a decrease in total ceramide content with some differences in the ceramide pattern.”

As with lab-isolated hyaluronic acid and peptides, the news on the ceramide front looks promising. The report goes on to say that “formulations containing lipids identical to those in skin and, in particular, some ceramide supplementation could improve disturbed skin conditions.”

We can’t promise you the baby-smooth skin you had as an infant, but your body possesses many of the building blocks it needs to maintain a solid skin barrier. All it needs is a little help. Add a wide-brimmed hat, quality sunscreen, and supportive skincare to your toolbox and you’ll be well on your way to counteracting fate. At least when it comes to skin.

Your Skin Barrier Support Group