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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 prevents viruses, bacteria, free radicals and other unhealthy factors from penetrating our tissues. But what happens when it is no longer, or temporarily no longer, healthy?

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

Is that enough? And are there actually care products that can also contribute to strengthening them? Or even care rituals that can harm or protect them? So let's talk a little about this and clarify a few things.

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

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

The epidermis plays the biggest role in the protective function of the skin, more precisely its outermost part - the horny layer (stratum corneum). This part of the skin is therefore most important for keeping moisture in the skin.

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The horny layer consists of dead cornified cells (corneocytes) and lipids surrounding them. This structure is most easily imagined as a brick wall, where the corneocytes 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 (about 15%) and cholesterol (about 25%). Any deficiency of 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 protection 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, mono- and disaccharides, which have a high ability to store water in the skin. These substances are formed by the breakdown of the protein filaggrin which has a structural role in the deeper skin layers. 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 loss of moisture occur?

Many factors can influence the condition of the skin barrier. Too frequent or insufficient skin cleansing can damage the protective layer of the skin. Equally aggressive cosmetic treatments or insufficient care products are predestined to negatively influence the so-called acid mantle of the skin. Further elementary factors are genetics and age.A damaged skin barrier can thus also be of genetic origin, e.g. in neurodermatitis. And the fact that the skin loses the ability to store moisture fromabout the age of 30 onwards is the reason why it is sensible to actively provide external support from this age at the latest.

A damaged skin barrier leads to a loss of moisture. Dry skin is the most frequent consequence of a damaged skin barrier function. Various skin diseases such as acne and herpes can also occur if the skin's own protective function is no longer intact.

How to strengthen the skin barrier and how to increase the skin moisture?

To increase the moisture of our skin, it is necessary to prevent the loss of water from the skin by strengthening the skin barrier. But before that it is necessary to increase the skin's ability to store moisture.

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

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

In addition, alpha hydroxy acids (AHAs) in low concentrations (< 2% - 5%) can be used to increase the skin moisture. These acids can bind water well and thus increase skin moisture.

Glycolic acid and lactic acid are most often used for this purpose as part of skin care products.

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 its ability to penetrate through the upper layers of the skin. It has the ability to provide moisture to the skin and also to increase the skin's ability to do the same.

Lactic acid is a natural component of the skin. As lactic acid is a larger molecule, it tends to act on the skin surface. In a concentration of 2%, lactic acid acts as a moisturizer.


The skin is our protective cover. It is important to make sure that the skin barrier is always in good condition and to strengthen it in the right way, especially with ceramides and natural oils. If we want to increase the moisture of our skin, substances such as hyaluronic acid, urea, glycerin and AHAs can also help us to do so.

This article 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 in her spare time she continues to dedicate herself to her favourite subject, skin and skin care. Minja runs her own blog and an Instagram profile, both under the title "The Soul of Skin".

Products in our shop that can help you to strengthen your skin barrier can be found here

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