Scientific progress made the Human Genome Project a reality. Since then, we have had a much better understanding of the intestinal flora and the cutaneous flora. Specialists have identified their composition more precisely, giving them a new name "microbiota". As with the stomach microbiota, the skin microbiota is closely linked to the health of the skin.

Cutaneous microbiota: what is it?

In the past, we used to talk about skin flora without really knowing what it was until Professor Richard Gallo, Chairman of the Department of Dermatology at the University of California, San Diego, began to study it. Twenty years ago, this professor began to analyse and decipher this skin flora to which he gave the name of cutaneous microbiota. This microbiota that covers the entire skin is a collection of 100 billion living microorganisms called probiotics. It consists of bacteria (75-80%), viruses (10-20%), and yeast or fungi (5-10%). There are approximately 1 million of these microorganisms per cm² of skin, which even slip into the folds and recesses of the skin, from the pores to the pilosebaceous follicles, where they each play a very specific role. Microorganisms that cooperate or otherwise compete with one another. The primary families of bacteria are Staphylococcus, Corynebacterium, Propionibacterium, and cutibacterium.  A thousand varieties (of probiotics but about 500 of bacteria) - with sub-varieties - that cohabit in perfect symbiosis with our cells. These essential probiotics feed on our skin secretions (lipids from sebum, proteins from dead cells, sugars, and water from sweat...). It was not until 2001 that the World Health Organisation recognised probiotics as "living micro-organisms that (...) exert positive effects on health" and ensure the proper balance and health of our microbiota.

What is the role of the cutaneous microbiota?

Skin microbiota plays a vital protective role for the skin. Its microorganisms form an arsenal of guards to preserve the integrity of the skin barrier. This skin microbiota forms a protective layer that reinforces this barrier and thus blocks the penetration of viruses and bacteria known as "pathogens", which could cause diseases. However, this interaction with the hydrolipidic film has many other functions. The skin microbiota maintains the physiological pH of the skin at around 5.5, which repels pathogenic bacteria that like a basic pH of around 8. Skin microbiota also stimulates skin cell renewal and has an important role in the skin's immune system. It helps them recognise attacks and respond most effectively. In addition, skin microbiota promotes the healing and repair of the skin. It is also involved in the secretion of antimicrobial peptides (which are like soldiers that attack and destroy invading bacteria) by the skin cells, antioxidant, antibacterial, and anti-inflammatory substances. In short, the role of the skin microbiota is crucial to the health of the skin.

What factors influence the skin microbiota?

Throughout one's life, the skin microbiota varies even if everyone has their microbiota.

• To each their own cutaneous microbiota

Everyone has a unique skin microbiota. It is a sort of personal signature just like DNA or fingerprints. This microbiota is passed on to the baby by the mother at the time of vaginal delivery. It will then evolve and become more diverse throughout one's life, particularly during each major hormonal change (adolescence, pregnancy, menopause/andropause). Its composition, or at least the proportion of varieties of microorganisms, differs according to the different parts of the body (scalp, armpits, arms, etc.). Some bacteria prefer dry environments (arms, legs), others moist areas (mucous membranes, armpits, folds, etc.), or oily areas with sebum (inside of ears, scalp, face, etc.). The skin microbiota also changes with age, gender, and ethnicity. The microbiota is the "exposome" of its host, i.e., the environment and pollution in which they live, but also their lifestyle, stress, diet, hygiene, age, sex, and medication, not to mention the people and pets that live with them. This explains why we have multiple skin microbiota, all different and varied (unlike our DNA which does not vary).

• Each imbalance in the skin microbiota leads to a symptom

We now understand that skin health comes from the balance and diversity of probiotics within the skin microbiota. Thus, as soon as one strain takes over or an intruder enters, there is an imbalance (or dysbiosis) that leads to inflammation that can result in disease. It has been discovered that atopic eczema (or atopic dermatitis), acne, or dandruff in particular, are linked to an imbalance in the microbiota caused and accentuated by our living conditions: pollution, medication, stress, UV, excessive hygiene, and certain cosmetic ingredients. Acne is partly caused by an overpopulation of cutibacterium acnes. Atopic dermatitis shows a great imbalance where Staphylococcus aureus is dominant. Dandruff is not caused by bacteria, but by the growth of a fungus on the scalp called Malassezia. But are these excess probiotics the cause or the consequence of the ailment? Researchers don't know yet…

In addition, several studies have shown that pollution alters the composition of the microbiota, which then resembles that of an older woman. Could the microbiota be linked to premature ageing? The researchers suspect it. However, since the discovery of the skin microbiota is only about fifteen years old, even if its study is progressing rapidly, we are far from understanding all its mechanisms and the extent of its influence.

How can skin microbiota protect the body?

• The skin microbiota has a natural protective function

The skin, the largest organ of the body, is also our main contact with the outside world. It is a protective barrier in which the microbiota plays an essential role. By strengthening the immune system, the skin microbiota protects the skin from infection, external aggression, and inflammation. This protection, which extends over the entire surface of the body, fights against transcutaneous intrusions.

• Skin microbiota can be strengthened

Cosmetic products and/or dietary supplements enriched with prebiotics, probiotics, and post-biotics contribute to preserving and rebalancing the skin microbiota to keep the skin healthy.

Probiotics are living microorganisms (bacteria, yeast, etc.) that make up the microbiota and maintain its natural balance. While they are found in fermented but unpasteurised dairy products and vegetables, they are absent from cosmetics where it is not possible to include a living organism. On the other hand, some skincare products contain fragments of probiotics (Lactococcus, Bifidobacterium, Lactobacillus, etc.), deactivated either by heat or by fermentation, which are detected and assimilated by the skin's probiotics. For marketing purposes, cosmetic brands indicate "with probiotics". Their antioxidant and anti-inflammatory properties ensure a beneficial ecosystem for the microbiota.

Prebiotics are simple or complex sugars, fats, or amino acids that nourish and promote the healthy development of skin bacteria. A sort of fertiliser for the microbiota, which is particularly beneficial in cosmetics. In food, this is the fibre in fruit and vegetables, particularly chicory, garlic, artichokes, and psyllium husk … In cosmetics, the best known are inulin, from chicory, and yacón. But some ingredients, such as glycerine, squalene, and polyphenols, which have been used for a long time in cosmetics, also happen to be prebiotics.

Post-biotics are molecules secreted by probiotics. The waste products, metabolites, or probiotic membranes, mimic them and balance the ecosystem in which healthy microbiota live. For example, lactic acid belongs to the post-biotic family. Some dermo-cosmetic brands prefer to develop their custom-made post-biotics, often using bacteria cultivated in thermal water to remedy specific problems: acne, atopic dermatitis, dry skin, etc.

The BLUE SKINCARE brand has chosen to incorporate pre- and post-biotics in all its skincare products and its cleansing products to offer formulae that respect the balance of the skin's microbiota, in particular with pre- and post-biotics (inulin and sugars), post-biotics (probiotic complex obtained by lysis of fermented Lactococcus Lactis bacteria and also lactic acid). To be found in the NACRE ÉCLAT range, dedicated to dull and tired skin, and in the XÉRO•NACRE range dedicated to uncomfortable skin prone to atopic dermatitis and psoriasis. All formulae have been developed to match the physiological pH of the skin.

How can the skin microbiota be restored?

To restore the skin microbiota and maintain its balance, here are 6 simple steps to take:

• Reduce underwater travel. With a pH of 7, water can destabilise the microbiota if you bathe too long and it's too hot.
• Choosing the right hygiene products: the discovery of these "beneficial bacteria" changed the "hygienic" vision since Pasteur. It was thought that bacteria and viruses were inevitably harmful. We now know that there are good and bad probiotics and that we must favour the "good" probiotics naturally present on the skin. So, no more "bactericidal" products at all. Shower gels with overly aggressive surfactants imbalance the microbiota, which can take over 4 hours to recover after each shower. So, one shower a day maximum, and with the gentlest possible cleanser.

The Lipid-Replenishing Cleansing Oil is a beneficial cleansing oil with a physiological pH composed of a unique complex of ultra-gentle cleansing agents, a trio of vegetable oils, and prebiotics (inulin and sugar) that cleanse the skin while respecting the hydrolipidic film and the skin microbiota.

• Maintaining the pH of the skin microbiota: Microbiota and skin pH are intimately linked through the hydrolipidic film that hosts the microbiota. As this film is called the "acid mantle", any product with the wrong pH should be avoided: the well-known Marseille soap, or any other soap, has a basic pH (above 7). We, therefore, prefer Lipid-Enriched Bar Cleanser. For the same reasons, but because of their very acidic pH, fruit acids should be used reasonably and with the proper guidelines. We, therefore, choose products with a "physiological pH" and not a "neutral pH", which means that they respect the skin's pH, whereas a neutral pH is 7.
• Avoid overly aggressive products (or limit their use), such as grainy scrubs or cosmetics containing a lot of alcohol.
• Gently remove make-up, without aggression, without rubbing, and avoiding the use of harsh cotton pads. The idea is to remove your make-up with your fingers by massaging to gently remove all impurities. To be applied in a circular motion, the Metamorphosis Balm is ideal for removing make-up and cleansing the skin effectively and effortlessly while maintaining the balance of the skin's microbiota thanks to its formula enriched with pre- & post-biotics. In the morning, do not scrub as suitable floral water is enough, or Use the Milky Micellar Water also rich in pre- & post-biotics. As fresh as water and as gentle as milk, it will delight in combination with oily skin. It can be massaged in gently to remove all impurities.
• Eating a balanced and diverse diet. Diet has an impact on the condition of the skin and the study of microbiota has revealed gut/brain and gut/skin axes. To have a rich and varied intestinal and skin microbiota, one should eat products rich in pre-and probiotics, such as garlic, onions, and all fruits and vegetables, which are rich in fibre, vitamins, and minerals. Spices and herbs have anti-inflammatory properties and help destroy pathogenic bacteria. And if that is not enough, you can take dietary supplements (the Skin Perfector Food Supplement, rich in active mother-of-pearl powder highly concentrated in calcium and amino acids coupled with pre-and probiotics, hyaluronic acid, vitamin C and zinc: the essential complement for all tired, lacklustre, and blemish-prone skin).

The discovery of the skin microbiota and its role has brought a new vision of cosmetics. Henceforth, laboratories try to formulate care products in such a way as not to disturb them, by limiting or even removing certain ingredients that could cause imbalance or even deterioration. These are mineral oils and silicones, but also emulsifiers (what foams like sulphates) and emulsifiers (what binds emulsions, creams, or fluids). Preservatives have also been criticised, but in the end, it seems that they do not influence the microbiota.

The body is in constant renewal throughout life. Virtually all organs, except neurons and heart cells, are completely renewed several times, at different frequencies, from one week for the liver to 4 months for the bones. The skin, which is an organ, is also renewed, thanks to the regeneration of its cells.

Cell renewal refers to the ability of cells to reproduce, that is, to produce genetically identical cells that take the place of other cells. At the end of their life, these cells eliminate themselves. Skin cell renewal is the process that leads to the elimination, each day, of thousands of dead cells, replaced by new ones. The right frequency of cell renewal, neither too slow nor too fast, is essential to maintaining a good barrier function, for radiant, uniform, smooth and energetic skin.

Where does skin cell renewal take place?

The epidermis, the superficial layer of the skin, is a bit like a Tetris game. It is a kind of wall made of bricks, keratinocytes, which are cells that are constantly rising towards the surface. These brick cells are born in the basal layer, at the bottom of the epidermis and gradually migrate towards the stratum corneum, the most superficial layer of the epidermis.

What is the mechanism of skin cell renewal?

As they move up from the deep -basal- layer of the epidermis towards the surface, the keratinocytes undergo different mutations. This is cellular differentiation.

• In the reservoirs of the basal layer are the keratinocyte stem cells. They divide to give rise to a daughter stem cell - which will replace it in the basal layer to divide later - and another keratinocyte, almost cubic and with a nucleus, which, pushed upwards by the new cells, begins its differentiation by rising to the upper level. This is cell proliferation.

• The spinous layer is the thickest of the epidermis, made up of 4 or 5 layers of keratinocytes. The latter, almost polyhedral in shape and swollen with water, weld to each other thanks to desmosomes and hydrophilic and hydrophobic substances. As they rise, they become loaded with keratin and melanin.

• The main transformation, called cellular differentiation, takes place in the granular layer. The granular layer is a transition zone that separates the living epidermal layers from the so-called "dead" layers of the horny layer. The keratinocytes are completely remodeled to become corneocytes. They gradually lose their nucleus and plasma membrane to make way for a rigid and insoluble envelope, the horny envelope. In addition, one of the differentiation markers, filaggrin, is transformed into free amino acids that constitute the "natural moisturizing factors" of the horny layer.

• Once they reach the surface, in the horny layer (or stratum corneum), the corneocytes are flat and filled with keratin, and clump together in a stack of cellular lamellae welded together by the intercellular cement made of lipids, to form the skin barrier. They eventually detach themselves thanks to enzymes that will break the snap fasteners that hold the corneocytes together, the desmosomes. This is desquamation. All this happens slowly and almost invisibly. Without realizing it, we lose about four grams of skin per day.

Cell renewal: how long?

Skin cell renewal is a bit like snakes shedding, except we don't let our skin shed in one piece in one day. Between the birth of a cell and its migration to the stratum corneum, 21 to 28 days normally pass. Keratinocytes spend very little time in the lower layers but remain in the stratum corneum for about 14 days. But the frequency of skin cell renewal naturally slows down with age. Cells become "lazier" and take much longer to migrate over the years. From the age of 50, the speed of cell renewal decreases by almost 40%. This is why we seek to "stimulate" cell renewal with specific anti-aging treatments.

What are the factors that affect cell renewal?

In a healthy epidermis, the quantity of cells eliminated on the surface is compensated by the production of new keratinocytes in an identical proportion. But it happens that the process goes awry, with slowed or accelerated proliferation.

• Accelerated renewal, healing and psoriasis When our skin is injured or infected, cell renewal intensifies in order to repair the injury - this is the healing process - or to fight the infection with new cells. This acceleration can reach seven times the rate of normal cell reproduction, or 3-4 days. A chronic inflammatory skin disease, considered an autoimmune disease, psoriasis is manifested by accelerated cell renewal in the affected area (knees, elbows, scalp, etc.), which no longer stops. New cells are born and rise to the surface at a faster rate than that of desquamation. Dead cells accumulate on the surface of the skin and end up forming plaques, the "scales". These plaques come off like scales, while underneath the cells, which jostle and pile up, create painful lesions that can bleed.

• Slowed renewal: stress, obesity, tobacco, pollution, UV rays, and age slow down skin renewal. The skin struggles to flake, dead cells accumulate on the surface because the bonds that hold skin cells together (desmosomes) do not detach as they should. These form a film that thickens the skin and makes the complexion dull and the skin rough. This accumulation also causes a loss of cohesion of the corneocytes, which are no longer able to effectively regulate the evaporation of water, hence progressive dehydration that leads to the premature appearance of fine lines.

How to renew skin cells?

To “boost” cell renewal, there are several possibilities, which can be combined.

Exfoliate

Exfoliating regularly – once or twice a week depending on your skin type – is the easiest way. This gives your skin a little boost to get rid of its dead cells. By sending the message to the skin that the dead cells have gone, the epidermis is encouraged to produce new ones. You can choose a mechanical scrub that removes “dead skin” by rubbing grains, pits or shells of crushed fruits and nuts, salt, sugar, etc. Practical on the body, but sometimes too abrasive on the face, this type of exfoliant can cause skin irritation, depending on the force applied and the type of grains. In fact, you need very fine and round particles, not angular ones (even if they are micro-angles).

This is why we often recommend – and even more so for sensitive skin – so-called chemical or enzymatic exfoliants, which produce uniform exfoliation by chemical degradation of cells. There are two types:

• Acids: these are the famous AHAs for Alpha Hydroxy Acids (glycolic acid, malic acid, mandelic acid), BHAs for Beta hydroxy acids (salicylic acid), or PHAs for Poly Hydroxy Acids (gluconolactone)... They produce a more or less gentle exfoliation: glycolic acid, smaller, penetrates more deeply, is ultra effective but can be irritating, when PHAs are much gentler but require more time to act. And promote skin renewal, unclogging of pores, a softer skin texture, better hydration...

• Enzymes: these enzymes (usually plant-based) “nibble” at the bonds between dead cells – the desmosomes – to detach them without damaging living cells or irritating the skin.

Choosing the right assets

In addition to fruit acids, there are certain active ingredients known to boost cell renewal. This is the case of retinol, a powerful anti-aging active ingredient, one of the benefits of which is to promote skin renewal through its keratolytic (desquamating) effect, but which can be irritating, particularly for sensitive skin. Hence the search for so-called "retinol-like" molecules of plant origin, which provide the same actions without the drawbacks, such as bakuchiol, harungana, sea fir, paillon bean, pelargonium essential oil. New, micronized mother-of-pearl powder introduced into facial care products has scientifically demonstrated that by inducing the expression of certain key proteins such as filaggrin, it stimulates the migration of keratinocytes to the surface of the epidermis to ensure the correct "turnover" of cell renewal which guarantees repair and regeneration of the barrier and the epidermis to maintain stronger, healthier and more radiant skin: skin in full health. A valuable action to which is added an anti-radical power and stimulation of the production of type I collagen fibers to preserve the density and youthfulness of the skin.

Eat well

Diet also has an influence on cell renewal. Favor foods rich in vitamin A and beta-carotene. Vitamin A is mainly found in ingredients of animal origin (eggs, butter, offal, liver). While beta-carotene, a precursor of this same vitamin but also a strong antioxidant, is present in orange fruits and vegetables (carrots, sweet potatoes, melon, peppers, leafy green vegetables). Foods rich in vitamin C (citrus fruits, kiwi, peppers) are also useful for good cell regeneration. In the NACRE ÉCLAT Range from BLUE SKINCARE, when the skin is tired and lacking radiance, we advise you to complete your beautiful skin routine by using the Skin Perfecting Food Supplement. Ultra concentrated in active mother-of-pearl, it also contains a complex of pre & probiotics to rebalance the intestinal microbiota, hyaluronic acid to maintain the hydration and elasticity of the skin. Rich in vitamin C and zinc, it is an antioxidant and contributes to the normal formation of collagen for plumper skin.

Have a good nighttime routine

Cell renewal peaks at night. No longer having to defend themselves from daytime aggressions, skin cells repair and regenerate between 11 p.m. and 2 a.m. It is even around 1 a.m. that skin activity is at its peak, multiplying cell renewal by three compared to the same mechanism at 1 p.m. It is therefore time to give your skin a treatment that will help this renewal by using a specific treatment such as the NACRE ÉCLAT New Skin Serum from the BLUE SKINCARE brand, ultra concentrated in active mother-of-pearl powder, NACR-45®. If the skin is dehydrated, we correct it. Because this skin renewal process is water-intensive. Good hydration, through treatments but also by drinking 1.5 liters of water per day, is therefore essential to support cell regeneration. Obviously, it is essential to sleep well, getting 7 hours of sleep if possible to give the skin time to regenerate.

One look in the mirror and you know what your skin looks like right now. But do you really know how to identify your skin type? And yet, there are clues that allow you to recognise your skin type and gain a better understanding of how it works.

 

We all get genes from our parents! Each individual has their own characteristics written into their DNA! As far as the skin is concerned, it is also a question of biological heredity. Because we human beings and all of our organs, including the skin, are entirely made up of cells, all of which carry our genetic code. We inherit a colour, a skin type (and hair type) and sometimes skin diseases (often inflammatory ones). Subsequently, lifestyle and beauty products used on the skin will have an impact, at which point we refer to the condition of the skin.

Bear in mind that the skin is a vital organ. It is the protective barrier between the body and the outside world. The skin is a kind of shield against pollution, knocks, bacteria, viruses, cold and heat. It is made up of three layers:

• The epidermis (the most superficial layer) which is in contact with the outside world
• The dermis (just beneath it)
• The hypodermis (the deepest layer)

The skin has its own blood vessels, which create a genuine irrigation system, and nerves, which transmit information between the brain and the skin, in particular sensory information. This information goes in both directions: from the brain to the skin (hmmm, I like a certain someone - cue blushing!), and from the skin to the brain (ouch, that’s hot, I've burned myself – time to whip my hand away).

How do you identify your skin type?

To identify skin type, we factor in what can be observed (such as the colour - pale or red, to a greater or lesser extent). Then we move on to how it feels to the touch (it’s rough, or soft, or bumpy, takes time to regain its initial shape when pressure is applied – all to a greater or lesser extent, etc.). Being able to categorise the skin allows us to gain a better understanding of its nature, its strengths and weaknesses, the factors that are likely to have an impact on its physiology, modify it or transform. That way we can embrace hygiene routines and use beauty products accordingly.

The skin of the face, upon which skin type hinges, also characterises the skin that covers the entire body.

What are the various skin types?

Skin type is a bit like eye colour: it’s something that you cannot change.

You can't change your skin type, but by factoring in its characteristics, you can gain a better understanding of it and anticipate how it might respond to certain things. Picture this: the skin is a large envelope measuring about 1.5 to 2 m², weighing between three and five kilos for the average person! From the soles of the feet to the scalp, the skin plays the role of a barrier at all times, as well as an incredible communication tool. The skin is neither completely smooth nor completely even. It is made up of folds and of multiple orifices, is sometimes hairless and sometimes covered with hair, nails or hairs.

Knowing your skin type, and treating your skin kindly, is the way to support it better on a day-to-day basis. You can do this by using beauty products that keep it healthy and looking good, into the long term. Not forgetting that caring for your skin equals caring for yourself as a whole, both physically and mentally.

Experts have identified four skin types: normal, dry, combination and oily.