Skin Barrier

by | Aug 19, 2020

What Is The Skin Barrier?

As the first line of defense to protect the human body, the skin barrier can effectively lock in moisture and help the skin resist the invasion of various germs.

There are many kinds of skin barriers in a broad sense, including physical barriers, pigment barriers, nerve barriers, immune barriers, etc. The skin barrier we usually refer to generally refers to the physical barrier, which is what we know stratum corneum and sebum film.

The skin barrier structure includes sebum film and stratum corneum. The sebum film covers the surface of the epidermis, and the stratum corneum is the outermost layer of the epidermis.

We can see from the picture that the human skin barrier is a kind of unique brick wall structure. What is the special significance of this structure?

The brick wall structure of the stratum corneum is composed of keratinocytes and intercellular lipids. The orange squares represent keratinocytes and the blue represents intercellular lipids. Keratinocytes contain natural moisturizing factors, which are composed of amino acids, pyrrolidone carboxylic acid and lactate. Intercellular lipids are composed of ceramide, cholesterol, cholesterol esters, and free fatty acids.

We all know that building a wall requires bricks and cement. Only the bricks have no cement, the walls made of them can easily collapse. In the same way, it is difficult to build a wall with only cement and no bricks. Therefore, to build a healthy skin barrier, there must be enough bricks and cement.

The brick refers to keratinocytes in the stratum corneum. A keratin cell is equal to a brick. Keratinocytes are dead, dead cells that make up the bricks in the skin barrier.

Cement refers to the oil between the gaps of keratin cells, also known as intercellular lipids. The stratum corneum composed of keratin cells is not completely closely connected, there will be many tiny gaps in the middle, and there will be intercellular lipids in these gaps(Mainly composed of 50% ceramide, 20% cholesterol and 30% free fatty acids). They are the cement that connects the bricks tightly together.

Skin Barrier Function

Humans have evolved for hundreds of thousands of years and have already formed an extremely sophisticated system.

As the first line of defense for the human body, the skin barrier can help the skin resist various foreign pollutants, such as air pollution particles, ultraviolet rays, dust mites, air germs, and various allergens. Only the health of the barrier has the health of the skin and the health of the human body.

A healthy skin barrier can help reduce the occurrence of skin diseases and delay skin aging. Therefore, it is the correct skin care concept to consolidate the important wall of the skin barrier and then carry out advanced skin care, to greatly enhance the efficiency of skin care.

Why Is The Skin Barrier Damaged?

Living in this harsh environment world. It is even more difficult to maintain a healthy skin barrier. With a little stimulation and temptation to the skin, it will be destroyed.

Several factors cause damage to the skin barrier:

  • The pressure of life and work
  • Environmental pollution and climate factors(Such as extreme heat, extreme cold, etc.)
  • UV damage
  • Unhealthy lifestyle(Such as staying up late, often eating irritating food, etc.)
  • Excessive pursuit of quick-acting beauty(Such as chemical peeling and various medical treatments, etc.)
  • Use unsafe skin care products
  • Inappropriate skincare(For example, excessive cleansing, unclear skin needs, random use of some highly irritating skin care products)

Many people pursue rapid beauty in the world, but their skin barriers are problematic. However, many people do not realize the importance of the skin barrier.

Many people only buy expensive, big-name, efficient skin care products. They don’t know when the skin barrier is damaged(That is after the original dense brick wall structure was destroyed), the large number of nourishing ingredients that we input into the skin can not be locked and absorbed well. A large part of it has penetrated it and secretly ran out. Some ingredients have not entered the skin at all.


Although you have been seriously skin care, finally found that you have been doing useless work.

Spend a lot of money, but the skin condition is getting worse. At this time, some people will blame skin care products for no use.

So how do you know if your skin’s barrier is damaged?

What Are The Reactions After The Skin Barrier Is Damaged?

Comparison of normal skin barrier and disrupted skin barrier. The normal skin barrier can prevent the loss of body water and resist the influence of external stimuli, such as bacteria, viruses, and toxins. Disrupted skin barrier is vulnerable to external damage and loss of epidermal moisture.

Usually damaged skin barrier will have the following manifestations:

A cartoon woman with red blood on her cheeks
  1. The skin is particularly sensitive, and from time to time there are papules, pustules, allergies, rashes, and inflammation. Even if you take good care, your skin still can’t stop sensitive skin.
A face with a damaged skin barrier. Most areas of this face have dilated capillaries and red cheeks.
  1. The moisturizing ability of the skin becomes poor, and there is a lot of oil on the face, but no matter how moisturizing, the face is always dry, often accompanied by tingling.

Some people feel that their faces tingle with some skin care products. It may not be the problem of skin care products, but the skin is telling you that the skin barrier is damaged.

Sometimes it may be that the skin care product itself contains some sources of irritation.

  1. Frequent acne breakouts and dull complexion.

How To Repair The Skin Barrier?

As with all skin problems, to solve a problem, you must first find the cause of the problem and solve it from the source.

Everyone has different skin types, different living habits, and different environments. So the specific reason can only be found by you from your daily habits.

If you really can’t find the reason. It is recommended that before the skin barrier is restored, avoid excessive cleaning, stop using cleansing masks, stop acid peel-off, stop using powerful skin care products (such as retinol, vitamin C, arbutin, and other whitening products).

Stop doing medical beauty.

Don’t stay up late, streamline skin care steps, don’t put too much burden on the skin.

After cutting off the cause of the damage to the skin barrier, we will use some products that repair the barrier. Before taking stock of the major repair products, I would like to first introduce some common skin barrier repair ingredients.

Which Skin Care Ingredients Can Effectively Repair The Skin Barrier?

We use skin care products with repair function to repair the skin barrier, directly or indirectly supplementing the ingredients similar to the stratum corneum and sebum film, thus simulating the environment of healthy skin.

The following ingredients are commonly used to facilitate the repair of sebum film:


Damage to the barrier will inevitably be accompanied by problems such as thin epidermis and reduced skin defense. At this time, we must provide the most basic closed protection for the skin with damaged barriers. On the one hand, it can avoid excessive loss of skin moisture. On the other hand, it can also replace the effect of the stratum corneum. It is equivalent to isolating external irritants and preventing the skin from being more damaged.

There are many such ingredients, like some oils(Such as mineral oil, petroleum jelly, etc.), silicone oil(Polydimethylsiloxane, silicone elastomer, etc.). The most outstanding of these is squalane and its twin brother squalene.

Squalane not only has a very good moisturizing function, but it can also open skin pores, promote blood microcirculation, and help repair damaged skin. Moreover, squalene’s brother squalene is an important part of the sebum film, so the affinity of squalane to the skin is particularly good, and there is almost no irritation.

Fatty acid

Mainly includes vegetable oils, such as shea butter, avocado oil, etc. They are rich in unsaturated fatty acids, easily absorbed by the skin, have a good moisturizing effect on the skin, can also help cell regeneration and promote microvascular circulation, repair the skin.

The following ingredients are commonly used to facilitate the repair of stratum corneum:


In addition to squalane, ceramide has excellent effects on the repair of the skin barrier. The cement of the brick wall structure of the skin is composed of ceramide, free fatty acids, and cholesterol. The reason why the cement can retain water is because of the presence of ceramide. Ceramide combines free fatty acids and cholesterol to form a tight bimolecular membrane.

The bimolecular membrane is filled between the keratinocytes, which can effectively prevent the loss of water, nutrients, and electrolytes in the body, and has an excellent moisturizing effect.

When ceramide is lost in large quantities, free fatty acids and cholesterol cannot be linked together, and a large amount of free fatty acids will flow to the skin surface, and the skin looks more oily. Supplementing ceramide can reshape the stratum corneum structure and restore its skin barrier function.

The bi-molecular structure of lipids between cells of normal skin is tightly arranged. The damaged skin loses a lot of ceramide, free fatty acids and cholesterol cannot be connected together.

At present, there are 12 kinds of ceramides, ceramide 1, ceramide 3, and ceramide 6, among which ceramide 3 is the best. Since ceramide 3 is extremely expensive, the amount of ceramide 3 added to skin care products is extremely small, and only a few brands will add it to an effective active concentration. So what is the difference between different types of ceramides?

Ceramide 3 has a similar structure to the materials that make up the stratum corneum of the skin. It can quickly penetrate the skin and combine with the water in the stratum corneum to form a reticular structure that locks in moisture and strengthens the skin barrier and rebuilds cells.

Ceramide 6 can improve the sebum membrane while inhibiting the active sebaceous gland secretion, which can strengthen the skin barrier and rebuild the cells.

Ceramide 1 can intensively repair the natural sebum film of the skin, strengthen the defense function of the skin’s surface barrier, and has a good sealing property to reduce water evaporation and loss.

The plant sphingosine in Lancome’s small black bottle has a similar effect because it is a precursor of ceramide.

Dipotassium glycyrrhizinate

Dipotassium glycyrrhizinate can anti-inflammatory, eliminates redness, promotes cell repair, shrinks, and expands capillaries, so as to achieve the purpose of alleviating red blood.

Dipotassium glycyrrhizinate not only does it have good anti-inflammatory and soothing effect on the skin, but it can also help the skin quickly repair the sebum film and restore the original barrier function of the skin.


Glycerin is a kind of very absorbent moisturizer, it can quickly help the stratum corneum restore water content.

Glycerin can also stimulate the skin to produce a channel protein that specifically transports water from the dermal layer up to the epidermal layer, ensuring the normal function of the entire epidermal layer.

It can fundamentally improve the water carrying capacity of the epidermis, Laying a solid foundation for the repair of the stratum corneum.

Sodium pyrrolidone carboxylate (PCA-Na)

Sodium pyrrolidone carboxylate is one of the important components of the natural moisturizing factor (NMF) in keratinocytes. It has good hygroscopicity and helps repair the stratum corneum.

I hope that all the beautiful women can polish their eyes, recognize some exaggerated publicity, take good care of their skin, and take good care of our skin barrier.