Skin Barrier Basics: Protection, Repair, And Everything Else You Should Know

Written by Kellie Reed, MD, Board Certified Dermatologist on September 5, 2023 No Comments

skin barrier woman

The “skin barrier” has become an extremely popular term in skin care marketing. Products from cleansers and moisturizers to serums claim to have ingredients that strengthen or boost the skin barrier. While it sounds complicated, the skin barrier is an essential part to our overall health and well-being. In this blog post, we will discuss the general purpose of the skin barrier, some common ways the skin barrier can become damaged, and provide some simple ways to protect or enhance the skin barrier to ensure healthy looking and feeling skin.

What is the Skin Barrier?

The stratum corneum, also known as the skin barrier or moisture barrier, is the outermost layer of your skin. Within this layer are corneocytes, which are special skin cells held in place with a combination of fatty acids, ceramides, and cholesterol.

The stratum corneum is the barrier between the external environment and the deeper layers of your skin and your internal organs. Without this protection, your body would be subjected to extreme environmental damage that would have serious consequences.

Anatomy of the Stratum Corneum

Your skin is made of several layers, and the most familiar are the epidermis, the dermis, and the subcutis. The epidermis and dermis are further divided into smaller layers. For the epidermis, this includes the basal cell layer, the squamous cell layer, the stratum granulosum, the stratum lucidum, and the stratum corneum. The skin barrier or stratum corneum is the outermost layer of the epidermis.

The stratum corneum is approximately 10 to 30 layers made of corneocytes, lipids, and other natural substances that moisturize the cells. The stratum corneum sheds dead keratinocytes continuously. The lost keratinocytes are replaced with new, stronger cells. Young skin sheds the cells fairly quickly, but cell turnover slows with age. On average, young skin sheds every 30 days, and older skin sheds the cells within 50 days.

What Does the Skin Barrier Do?

The skin barrier is extremely important to the overall health and normal functionality of the skin. Being a barrier, the primary function of the stratum corneum is to serve as a shield that protects deeper layers of skin. Your body is constantly exposed to circumstances that are potentially harmful to your skin, internal organs, and overall health. The skin barrier fends off bacteria, UV rays, pollutants, and other agents.

However, it also serves as a gate keeper that regulates hydration (moisture) and body temperature. Both of which play key roles in the skin’s overall health and appearance.

Protection from External Factors

The stratum corneum provides your body with a protective barrier against physical and chemical infiltration. Physical factors include harmful UV rays from sunlight. Chemical factors include pollutants in your environment.

Regulation of Water Loss

The structure of the stratum cornea prevents trans-epidermal water loss, which is an excessive reduction in hydration and moisturization. Maintaining optimal hydration keeps your skin healthy and is important for your overall health. Many physiological functions, such as heart rate, blood pressure, and nutrient absorption, depend upon proper hydration in the body.

Defense Against Pathogens

The skin barrier is comprised of antimicrobial peptides that are part of your immune system. The peptides protect your body from fungi, bacteria, viruses, and parasites. When these substances come into contact with your skin, the stratum corneum works to prevent them from entering the deeper layers of skin and possibly reaching your bloodstream and internal organs.

Signs of a Damaged Skin Barrier

Despite the incredibly stable structure of the stratum corneum, our skin barrier is susceptible to becoming damaged. Skin barrier damage may be short-term (like a brief rash) or long-term as is often the case with chronic skin conditions like eczema and psoriasis. You can monitor the health of your skin barrier by watching for certain signs, such as:

  • Patches of scaly, rough, flakey, dry skin
  • Frequent skin infections
  • Frequent allergic reactions
  • Redness and inflammation

Any form or degree of damage can keep the skin barrier from functioning at its best; resulting in several potential issues that could negatively impact skin health.

Common Skin Barrier Disorders

Dry skin, eczema, and acne are the three most common skin barrier disorders. Dry skin is caused by a lack of hydration and oils in the skin. Proper cleansing and moisturizing daily are the best ways to treat and prevent this type of damage.

Eczema, also known as atopic dermatitis, is a chronic condition in which the skin is inflamed and itchy. Some people develop red patches as a result of eczema. Working with a dermatologist helps you understand the condition, triggers, and treatments to protect your skin barrier. Lifestyle changes and medications may help to reduce the severity and frequency of eczema symptoms to protect your skin barrier.

Acne is a complex skin condition that affects people of all ages. Studies have shown that people with chronic acne have lower levels of ceramides, a key substance in a healthy stratum cornea. Using acne treatment products containing ceramides may help boost the skin barrier while reducing the severity of your acne.

What Causes Damage to the Skin Barrier?

Numerous factors can cause damage to the skin barrier. Some factors like exposure to allergens or the use of overly powerful skin care ingredients can be controlled through lifestyle changes. Other factors such as genetics, chronic skin conditions, and natural aging are obviously outside our control.

Environmental Factors

The exposure (or over exposure) to various environmental factors including the following:

  • Exposure to sunlight
  • Pollutants (and overall air quality)
  • Allergens
  • Long term exposure to dry air (like through the user of a heater)
  • Lower humidity levels

Lifestyle Factors

Studies have shown daily lifestyle factors can contribute to damaging the skin barrier. Common factors include:


Natural aging leaves the stratum corneum most susceptible to becoming damaged. While this factor is out of one’s control, following a skin care regimen focused on maintaining skin health can help combat the effect of aging on the skin barrier.

Using Overly Powerful Skincare Ingredients

Skincare products that are intended to improve your skin tone and texture may contain ingredients that are harmful to your skin barrier. Some examples of known skin barrier affecting ingredients include retinoid acid, hydroxy acids, amino fruit acids, and beta hydroxy acids. Also watch for alkaline products that can disrupt the skin’s normal PH levels as well as products that contain isopropyl parabens, formaldehyde, and isobutyl.

Performing Harmful Skin Care Practices

Hot showers, over cleansing, and over-exfoliating damage the stratum corneum. These practices affect how the cells are arranged and may break down the lipids, cholesterol, and other substances that hold the cells together. As a result, environmental substances are able to penetrate your skin while moisture escapes.

How to Maintain a Healthy Skin Barrier

Fortunately, there are many ways protect the skin barrier to ensure it functions optimally. Harsh chemicals and sun exposure are the two most common causes of skin barrier damage. Fortunately, you can protect your skin barrier from these harmful factors.

Sun Exposure

Apply a high-quality broad-spectrum SPF 30 or higher sunscreen approximately one hour before going outside, and continue to apply it as recommended while you are outdoors. Its also a great idea to limit your time outdoors during peak UV hours.

Harsh Chemicals

Use soaps and laundry detergents with skin-health friendly ingredients. Often these products will be free of fragrance and other additives. Also check the ingredients of all skincare products. If you are uncertain about a specific ingredient, look for other products that are labeled with more skin-friendly ingredients.

Additional ways to help the skin barrier function its best include:

  • Keeping your showers short and use lukewarm water
  • Moisturizing after every shower or bath
  • Using a soft, clean washcloth rather than loofah or scrubs
  • Limiting exposure to low humidity and cold temperatures
  • Limiting or completely refraining from exfoliating
  • Working with a dermatologist for any chronic skin conditions, such as acne, eczema, and psoriasis

Skin Care Routine for a Health Skin Barrier


As you probably already know, cleansing is an important part of your daily routine. However, it is important to keep the skin barrier in mind when cleaning your face. Make sure to choose a product that is right for your skin type and is will not be overly harsh. Make sure to follow the instructions regarding the frequency of using the product. Avoid products that scrub the skin, as this will cause irritation and break down your skin barrier. If you notice your skin becomes irritated or overly dry after cleansing, consider changing to a milder cleanser.


High-quality moisturizers help your skin stay hydrated, a critical factor in keeping the skin barrier healthy. Be sure to moisturize regularly and opt for a product that is focused on calming the skin. The best moisturizing ingredients for your stratum corneum include:

  • Oat beta glucan
  • Ceramides
  • Glycerin
  • Ethyl linoleate
  • Hyaluronic acid
  • Panthenol
  • Niacinamide
  • Allantoin

Antioxidant Serums

Finally, consider adding an antioxidant-rich serum or product to your nightly routine. Vitamin C is a great antioxidant ingredient that can help shield the skin barrier from damage caused by free radicals and other external factors.

How to Repair an Already Damaged Skin Barrier

If you have signs of a damaged skin barrier, it is important to change your skincare routine. Three quick changes can often stop skin barrier damage:

  • Remove any “harsh” skin care products that contain fragrances, dyes, and other unnecessary ingredients.
  • Switch to a mild hydrating cleanser, one that is focused on being gentle
  • Stop (or decrease) exfoliating

To help the stratum corneum heal, use a thick moisturizer each day that contains ingredients to support the skin barrier, such as hyaluronic acid and glycerin. Ceramides and occlusive moisturizers are also beneficial.

How Long Does It Take to Repair a Damaged Skin Barrier?

The time it takes to repair your skin barrier depends on the extent of the damage. If you have a few areas of dry skin, your skin barrier may heal within seven to 14 days with proper support. More advanced damage may take six weeks or more to heal. Support the healing process by changing to gentler skincare products, adding humidity to the indoor air, and taking lukewarm showers and baths.

Kellie Reed, MD

Dr. Kellie Reed specializes in aesthetic skin care, general medical dermatology, pediatric, and rheumatologic dermatology. She is passionate about her patient care and attention to detail, and her positive attitude provides a sense of comfort for her patients. Dr. Reed is a member of the Travis County Medical Society, Texas Medical Association, Texas Dermatological Society, Austin Dermatological Society, Women’s Dermatologic Society, Rheumatologic Dermatology Society, and the American Academy of Dermatology.

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