The skin and its barrier function

The skin barrier and its health is an important topic. After all, the skin is our largest organ and the protective mantle of our body. When healthy, it keeps viruses, bacteria, free radicals and other unhealthy factors from entering our tissues. But what actually happens when it is no longer, or temporarily no longer, healthy?

Drinking plenty of fluids (preferably water and unsweetened tea), getting enough sleep (although "enough" is individual), getting enough physical exercise (to stimulate metabolism and circulation) and, best of all, plenty of fresh air in nature are the basics that everyone can implement in terms of a healthy lifestyle.

Is that enough? And are there actually care products that can help strengthen them as well? Or even care rituals that can damage or protect them? So let's talk a little about it and clarify some things.

What exactly is the skin barrier and why is its consideration, especially in skin care, so important?

One of the basic functions of the skin barrier is its protective function. On the one hand, it prevents the penetration of foreign substances and microorganisms from the external environment into our body, and on the other hand, it protects the body from moisture loss.

The greatest role in the protective function of the skin is played by the epidermis, or more precisely its outermost part - the horny layer (stratum corneum). This part of the skin is therefore the most important to retain moisture in the skin.

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The horny layer consists of dead keratinized cells (corneocytes) and lipids surrounding them. This structure is most easily imagined as a brick wall, where the horny cells are the bricks and the lipids are the cement in between.

The lipid mixture (cement) surrounding the cells consists of ceramides (on average 50%), fatty acids (approx. 15%) and cholesterol (approx. 25%). Any deficiency in any of these components represents a damaged skin barrier!

How else does the skin protect itself from excessive water loss?

In addition to the lipid protective layer, our skin has the Natural Moisturizing Factor (NMF), a "natural moisturizing factor".

This is a mixture of low-molecular substances such as amino acids, lactic acid, urea (urea), mono- and disaccharides, which have a high ability to store water in the skin. These substances are formed by the degradation of the protein filaggrin, which has a structural role in the deeper layers of the skin. Filaggrin is an important structural protein in the stratum corneum of the epidermis. Unfortunately, the occurrence of filaggrin cannot be influenced.

How does damage to the skin barrier and moisture loss occur?

Many factors can influence the condition of the skin barrier. On the one hand, too frequent or, on the other hand, insufficient skin cleansing can damage the protective layer of the skin. Aggressive cosmetic treatments or inadequate skin care products are also predestined to have a negative influence on the so-called acid mantle of the skin. Other elementary factors are genetics and age.A damaged skin barrier can therefore also be of genetic origin, for example in the case of neurodermatitis. And the fact that the skin loses its ability to store moisture fromaround the age of 30 explains why it makes sense to provide active external support from this time at the latest.

A damaged skin barrier leads to a loss of moisture from the skin. Dry skin therefore occurs as the most common consequence of a damaged skin barrier function. Various skin diseases, such as acne and herpes, can also be the result of a damaged skin's own protective function.

How to strengthen the skin barrier and increase skin hydration?

In order to increase moisture in our skin, it is necessary to prevent water loss from the skin by strengthening the skin barrier. Preceding this is the need to increase the ability of the skin to retain moisture.

The best way to strengthen the skin barrier is to provide the skin with structural lipids. These include ceramides, plant oils, essential fatty acids and cholesterol, which are themselves part of the horny layer.

To increase the skin's ability to retain moisture, we need substances that are part of NMF, such as urea or amino acids. Components such as hyaluronic acid (from short to medium to long chain), peptides & proteins, glycerin and propylene glycol also help the skin retain moisture.

Da sie die Fähigkeit besitzen, Wasser an sich zu binden, können zudem Alpha-Hydroxysäuren (AHAs) in geringen Konzentrationen (< 2% - 5%) verwendet werden, um die Hautfeuchtigkeit zu erhöhen. Glykolsäure und Milchsäure sind zwei bekannte Beispiele für AHAs und werden zu diesem Zweck am häufigsten als Teil von Pflegeprodukten verwendet.

Glycolic acid is the best known and most effective alpha hydroxy acid. What makes glycolic acid so special is its very small molecule size and ability to penetrate through the upper stratum corneum into deeper layers of the skin. Glycolic acid has the ability to deliver moisture to the skin and, in parallel, can increase the skin's ability to retain that moisture.

Lactic acid is a natural component of the skin. Since lactic acid is a larger molecule, it acts more on the surface of the skin. At a concentration of 2%, lactic acid acts as an ideal moisturizer.

Conclusion:

The skin is the protective cover of our body. To support its function and make it resistant, it is important to make sure that the skin barrier is in an intact state. We can and should strengthen it in the right way, especially with ceramides and natural oils. It is also important to increase the moisture in the underlying layers of the skin and to support the skin in its ability to retain this moisture permanently. We achieve the latter with substances such as hyaluronic acid, urea, glycerin and AHAs.

This post was written by our guest writer Minja. Minja studied pharmacy and then specialized in skin care for another two years. She works as a pharmacist and continues to devote her free time to her favorite topic, skin and its care. Minja runs a blog and an Instagram profile herself, both under the title "The Soul of Skin".