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Healthy-looking skin is linked to a well-functioning skin barrier. Here at Kiehl’s, learn what the skin barrier is, what it does, and how to care for it.


What Is The Skin Barrier? Here’s What You Should Know

What You Should Know About The Skin Barrier

Here’s a fun fact: Your skin is your largest organ, making up around one-seventh—or nearly 15%—of your total body weight. It’s what separates your delicate insides from the harsh outside world, making it one of the most important organs in your body. Skin is composed of a vast, complex network of various cells, proteins, ceramides, and lipids—but arguably, the most vital component of all is the skin barrier, sometimes referred to as the skin’s natural moisture barrier.

If you’re a Kiehl’s fan, you’ve likely seen us mention the skin barrier at some point—it’s what helps keep good things (like water) in and bad things (like pollutants) out. As such, maintaining a healthy skin barrier is essential for skin that looks and feels its best. To help you properly care for this vital system, we’ve put together this guide. Here, you’ll learn what the skin barrier is made of, how it works, and discover some of its vital functions. Plus, we’ll teach you how to maintain your skin barrier with some of our favorite Kiehl’s products. Keep reading for our crash course on the protective skin barrier.

What Is The Skin Barrier?


In order to understand what the skin barrier does, you need to know how the skin is structured. You’ve probably heard that the skin is made up of three individual layers. That’s not entirely true. While there are three main layers of skin (the epidermis, dermis, and hypodermis), each has several sublayers, most of which perform unique, specialized functions. For this article, however, we’ll be focusing on the topmost layer: the epidermis.

The outermost part of the epidermis is the stratum corneum, or the skin’s protective barrier. Scientists often liken the stratum corneum’s structure to being like a brick wall. In this analogy, the skin cells are the bricks. Everything else—including the skin barrier—is the mortar that holds it all together. This mortar contains essential nutrients like cholesterol, ceramides, and fatty acids. Together, these compounds are referred to as the skin’s "natural moisturizing factor" because they help keep the deeper layers of skin hydrated and nourished.

What Are The Main Skin Barrier Functions?

The skin barrier has several jobs, many of which are related to your health. Of all of the skin barrier’s duties, researchers generally agree that it has three essential roles: Protecting your body from external stressors, like pollution and UV radiation, retaining water to keep your body and skin hydrated, and transporting vital nutrients to your skin.I As a whole, these combined factors are responsible for maintaining homeostasis—in other words, keeping your body’s various systems balanced.

Your skin barrier is also the primary determinant of how healthy and even your skin looks. If you have a strong skin barrier, it will be able to retain water efficiently, keeping your skin hydrated, smooth, and elastic. It’ll also help fend off environmental aggressors, like pollution, and be less prone to skin concerns like sensitivity and irritation.

On the flip side, if your skin barrier isn’t working as it should, your skin will be vulnerable to damage. It’ll be more prone to dehydration, or trans-epidermal water loss, resulting in a dull, dry appearance. You’ll also be less able to fend off damaging aggressors, like free radicals. This is notable because free radicals can result in physical changes such as discoloration, laxity, and premature wrinkles. In fact, experts estimate that environmental influences are responsible for up to 97% of visible skin aging.II In other words, many of the most common skin concerns can often be connected to a poorly-functioning skin barrier.

What Can Cause a Weak Skin Barrier?

It would be nearly impossible to list every potential source of skin barrier impairment; everything from your genetic makeup to your lifestyle can affect skin barrier health. The most significant factors that can impair barrier function include UV radiation, smoking, and chronic exposure to pollution. Physical damage—like that incurred from over-exfoliating—can also affect your skin barrier’s health, as can lifestyle factors, like your stress levels and how much sleep you get. Think of it this way: Any internal or external stressor that results in visible skin changes is likely capable of disrupting or damaging your skin barrier. Avoiding these stressors can protect your skin barrier, and in turn, help promote a healthy appearance.

How Should You Care For a Damaged Skin Barrier?

Ultra Facial Advanced Repair Barrier Cream

Dryness, discomfort, and heightened sensitivity are all signs that your skin barrier may not be working as it should. Addressing these concerns requires caring for your skin barrier by replenishing moisture and essential lipids. This should include reaching for soothing, hydrating products. Utilizing a barrier cream, such as Ultra Facial Advanced Repair Barrier Cream, can be incredibly helpful as well. This intensive repair cream with colloidal oatmeal is uniquely formulated for dry skin prone to distress. It helps restore the skin barrier and works to relieve the discomfort and irritation associated with barrier dysfunction.

How To Protect Your Skin Barrier: Our 6-Step Routine

Now that you know what the skin barrier is and how it works, we can get into the fun stuff: specifically, skincare. While skincare alone won’t prevent barrier damage, the right routine can have a dramatic impact on your skin’s texture, resilience, and overall appearance. Read on for a complete routine designed to help protect and maintain your skin barrier.

Step 1:

Gently Remove Dirt and Debris

If you want your skin to look and feel its best, cleansing is a must. Washing your face helps remove the dirt, oil, and pollutants that accumulate on your skin throughout the day and helps prevent them from damaging your skin barrier.

Start your routine off with our cult-classic Ultra Facial Cleanser. This Kiehl’s staple with squalane and avocado oil removes dirt, excess oil, and other impurities without stripping or over-drying the skin. The ultra-gentle formula is pH-balanced to help maintain the skin’s protective barrier, and it’s uniquely formulated to be suitable for all skin types, even sensitive skin. Dispense a dime-sized amount of this mild cleanser onto clean hands and massage it over your face in a circular motion. Then, rinse thoroughly with lukewarm water (super-hot water can dehydrate your skin—not a good way to start your routine).

After rinsing off your cleanser, dampen a clean cotton round with Calendula Herbal-Extract Alcohol-Free Toner and gently swipe it over your face. This calming toner, which contains calendula extract and allantoin, helps soothe the skin, relieving discomfort and visibly diminishing redness. The alcohol-free formula is non-drying and non-comedogenic, and it can be used daily for balanced, fresh-feeling skin.

Step 2:

Apply a Targeted Facial Serum

Vital Skin-Strengthening Hyaluronic Acid Super Serum

After cleansing and toning your skin, we recommend applying a targeted facial serum—though the formula you use should be tailored to your specific needs. If your primary goal is to strengthen your skin barrier, we suggest using Vital Skin-Strengthening Hyaluronic Acid Super Serum. Formulated with 11kDa hyaluronic acid (our smallest version of hyaluronic acid) and a blend of adaptogenic herbs, this unique serum is clinically-demonstrated to double skin’s strength and boost resilience.* It also helps neutralize the damaging effects of external skin-aging stressors and improves skin texture, giving way to a more youthful, radiant appearance over time.

If dryness or dehydration is a concern, Hydro-Plumping Hydrating Serum may be ideal for you. This ultra-gentle facial serum with 15% glycerin deeply hydrates the skin, leaving it plumper, smoother, and more even-looking. The dermatologist-tested formula is fragrance-free and suitable for all skin types—you can even use it on your delicate eye area.

*Based on a 4-week clinical study on 58 subjects tested in urban and polluted environments. Based on Strength Index = Composite, average score of clinically graded parameters after using the product for four weeks vs one week of use.

Step 3:

Lock In Hydration

If your skin is dehydrated, it can’t perform its essential functions properly—which, as we described above, can result in the formation of countless skin concerns. Help keep your skin hydrated by moisturizing morning and night with a lightweight face cream, like our classic Ultra Facial Cream with Squalane. The fast-absorbing formula absorbs easily, delivering lightweight hydration that lasts up to 24 hours. Additionally, the unique moisturizer helps restore, strengthen, and protect the skin barrier, helping it retain moisture. This best-selling face cream is suitable for all skin types, and it can be used daily for soft, smooth, healthy-looking skin.

Don’t forget to give your eye area a little love, too. Keep this delicate skin moisturized with the help of Avocado Eye Cream, a rich, nourishing eye cream made with shea butter and avocado oil. The concentrated formula delivers all-day hydration and helps protect your eye area against digital fatigue caused by blue light. Plus, it’s clinically-demonstrated to de-puff and brighten the under-eye area in a single use.*

*Results based upon expert grading evaluated with product in a four-week clinical test.

Step 4:

Reach For a Nourishing Face Oil

Face oils can also be a beneficial part of your healthy skin barrier routine—particularly if they contain antioxidants, like Daily Reviving Concentrate. This daytime face oil with ginger root essential oil and sunflower oil helps defend the skin against external stressors and damaging free radicals. At the same time, the non-comedogenic formula helps reduce the visible signs of fatigue to promote a more radiant, glowing appearance. As with most facial oils, a little goes a long way: Just pat two to three drops onto your skin after moisturizing for fresh, healthy-looking skin.

Step 5:

Protect Your Skin With SPF

Last but not least in your daily routine is the most important step in keeping your skin both physically healthy and healthy-looking: sunscreen. In addition to protecting your skin against painful sunburns, sunscreen is instrumental in helping to reduce the risk of skin cancer. It’s also one of the most effective weapons in your anti-aging skincare arsenal, as studies show approximately 80% of skin aging results from UV radiation.

Super Fluid UV Defense Daily Facial Sunscreen SPF 50+

For lasting protection, apply a broad-spectrum sunscreen as the final step in your skincare routine every morning (yep, even in the winter). We recommend Super Fluid UV Defense Daily Facial Sunscreen SPF 50+, which offers both UVA and UVB protection. The lightweight formula contains antioxidants, including vitamin E, which help protect against other environmental stressors, like airborne pollution. The daily-use sunscreen is non-comedogenic, suitable for all skin types, and absorbs quickly with a matte finish. Apply it at least 15 minutes before any sun exposure and reapply throughout the day—ideally, every two hours or after sweating or swimming.

Bonus Step: Replenish Your Skin While You Sleep

You don’t have to put in a ton of effort to protect your skin barrier—in fact, you don’t even have to be awake. An overnight mask, like our Ultra Facial Overnight Hydrating Mask With 10.5% Squalane, can do some of the heavy lifting while you sleep. This transformative balm-to-oil mask with 10.5% squalane replenishes the skin’s moisture barrier, stabilizing it and helping to boost resilience against damaging external stressors. Additionally, the leave-on formula helps reduce excess overnight moisture loss and prevents dryness for up to three days. We recommend applying a generous layer to clean skin three nights per week right before bed. When you wake up, there’s no need to rinse—just proceed with your usual morning skincare routine for nourished, healthy-looking skin.


I. Rosso, James Del et al. "Understanding the Epidermal Barrier in Healthy and Compromised Skin: Clinically Relevant Information for the Dermatology Practitioner: Proceedings of an Expert Panel Roundtable Meeting." The Journal of clinical and aesthetic dermatology vol. 9,4 Suppl 1 (2016): S2-S8.

II. Zhang, Shoubing, and Enkui Duan. "Fighting against Skin Aging: The Way from Bench to Bedside." Cell transplantation vol. 27,5 (2018): 729-738.

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