Would you have imagined for a single moment that the skin was the largest organ in the human body ? You wear on average 4kg of skin every day! If we unfolded it completely on the ground [yuck] it would represent 2 square meters of surface area... But this skin mass is not only important because it takes up space. Indeed, all over the world and since the dawn of time, the skin has been a real communication medium. Men and women have always used pigments to make up their faces and bodies . Their goals? On the one hand, to beautify yourself. On the other hand, mark particular circumstances of life such as weddings or funeral rituals. Today, more simply, your skin envelope embodies your identity. It is a reflection of your lifestyle , your stress , your state of health and your age . It even betrays your emotions . It is what separates you from the outside world and gives you information about the latter via the 2000 sensors per cm2 found there. Like a shield , it protects you from attacks . And yet, this faithful defender remains no less fragile : she must be looked after. Understanding it better to better maintain it is what we offer you in this article.
Seen from the outside, the skin has a smooth appearance. We do not suspect for a moment all the complexity that is hidden there. Use a microscope at the lowest magnification to observe its extreme finesse. How can we suspect that this single millimeter of thickness is in fact a microscopic sandwich? A real mille-feuille? A 5-story building? When we zoom in further, the different layers which constitute this tissue with a thousand mysteries come into view, as well as an incredible number of cells and fibers which enter into their composition. The advantage of this division into layers lies in equitable sharing of tasks and in a real synergy of inter-layer actions. All together, they act to maintain good skin function.
Let's take the elevator that goes through the layers of our skin, from the deepest to the outermost and stop at each floor.
1) On the ground floor: HYPODERME
This first layer on which the others rest and the one you like the least because it contains fat . This is actually a reserve fabric . In other words, when you need energy , the body will look for fats from this tissue to transform them into energy . This is made possible thanks to special cells capable of storing and removing storage. This is where weight loss and weight gain come into play. This fatty layer intertwined with blood vessels is our 100% natural coat which protects us from temperature variations.
2) First floor: the DERMIS
The dermis is impressive since it is significantly larger in proportion than the other layers. It can be compared to the skin mattress which contains all its structural elements (frame, springs, foam, etc.)
a) Extracellular matrix
The dermis is made up of an extracellular matrix , a sort of jelly in which all its components are bathed: collagen and elastin fibers and hyaluronic acid . This substance plays a role of the foam contained in the mattress which supports the other elements and provides comfort .
b) Collagen fibers
Collagen fibers , like the springs of the mattress, provide structure to this dermal mattress . They therefore give the skin its strength and firmness but also its elasticity and suppleness . It can then be deformed without being altered and return to its initial state.
When we are children or young people , our skin is tight and therefore smooth and elastic . With each facial expression (when we speak, smile, grimace, squint our eyes), temporary folds appear. The skin then easily returns to its initial taut state because the collagen capital is intact. The fibers work well and correctly ensure the perfect elasticity of the skin to avoid the persistence of folds and therefore wrinkles.
Then over the course of life, the first signs of aging appear by impacting the physical properties of the dermis . Indeed, as we age, skin cells lose their vigor and synthesize less collagen. In addition, existing fibers are altered . Each additional year of life means 1% less of our collagen capital. So at age 80, 75% of our collagen capital is gone. Result ? The skin loses firmness and elasticity , becomes loose and wrinkles. It returns less and less well to its initial position. From the age of 30, the first wrinkles appear. It is therefore important to preserve your collagen capital for as long as possible by providing collagen to your body or by stimulating its natural synthesis . At Reborn, we opted for the second option , more sustainable and more effective . Our Gold & Glow skin perfecting gummies contain vitamin C , known to stimulate the body 's natural production of collagen . Enough to guarantee you eternal youth .
Also pay attention to overexposure to solar rays which penetrate the tissues and accelerate the deterioration of collagen , slow down its production and therefore aggravate the aging phenomenon.
c) Hyaluronic acid
Collagen fibers are associated with hyaluronic acid molecules which have the fabulous power to absorb 1000x their weight in water , like a super- sponge . This will help deeply hydrate the skin . This absorbent element also maintains the different component fibers of the dermal mattress , which allows it to maintain its firmness and tone .
d) Elastic fibers
What would collagen fibers be without elastin fibers ? Other springs , different but complementary, acting in perfect osmosis to guarantee optimal stretching capacity of the skin.
e) Hair follicles
Hair , eyelashes and hair are formed inside small sheaths dug into the dermis : hair follicles . These cavities continue into the epidermis with the pores , thus forming a sort of conduit between the dermis and the epidermis .
Hair also plays a role in maintaining body temperature . When it's cold , we shiver . The horripilatory muscles located in the dermis contract. This action causes the tissues in the skin to heat up . When these muscles contract, the hairs stand up: you get goosebumps . Straightening the hairs allows more air to be stored, which then serves as thermal protection , like the air today on double glazing. Hair is therefore a legacy of our prehistoric ancestors who were much hairier than us and much less clothed. Their body then adapted to the environment with hair as a temperature regulator. Today the straightening of the hairs is a natural mechanism but their quantity being less important, this no longer allows us to protect ourselves as well from the cold . We must therefore add a little fur on the back.
g) Sebaceous glands
Sebaceous glands are attached to the follicular duct in the dermis. They produce sebum , a very important liquid in the formation of the hydrolipidic film , the last layer of the skin . Secretory organs responsible for blackheads , papules and pustules , these unsightly imperfections .
Normally, the sebum produced by these glands is supposed to drain away debris from dead skin cells . It happens that the latter clump together and block the hair follicle . Nothing is then visible on the “head” side. On the other hand, things go wrong on the “tails” side. In fact, the sebum that cannot be evacuated accumulates inside this reservoir where bacteria will also develop. At this stage, two possible scenarios:
- The comedo , that is to say the sebum transformed by the bacteria succeeds in piercing the plug . A black spot then forms which will eventually disappear.
- The hair follicle remains hopelessly blocked . The reservoir bursts inside the skin . It is the immune reaction that will cause tissue inflammation .
Note that you should never pierce a pimple for many reasons: you do it very badly, you can't see well, you don't have the right instruments and very often this leaves a small mark which can remain. . It is up to the doctor or dermatologist to decide whether to remove blackheads and whiteheads by doing what is called a dermatological skin cleanse.
Acne affects 80% of adolescents, girls and boys, but unfairly some more than others. This is a normal phenomenon because puberty hormones stimulate sebum secretion . It is particularly visible on the back , thorax and face because these are areas heavily populated with sebaceous glands. But don't worry, acne is not an infectious disease and is therefore not contagious. Certainly, in the acne lesion there are microbes but they are normal inhabitants of the skin which have developed a little more. It is therefore useless to use antiseptic products as some people do, thinking they are doing the right thing. On the other hand, if you have a lot of spots it is better to treat yourself with a suitable treatment.
g) Sweat glands
The sweat glands produce sweat . The latter plays a key role in maintaining optimal body temperature at 37°C. Because yes, the body is equipped with a thermostat . And, when we cross this limit, during extreme heat or physical exertion, our 3 million sweat glands come into action to make us sweat . Because by sweating , counter-intuitively, we cool down . Contrary to what one might think, sweat does not dissipate heat : it is not hot water that comes out of the pores . Cooling occurs through another physical phenomenon. Sweat comes out of the pores and spreads over the skin to evaporate . To go from the liquid state to the gaseous state it needs energy which it will pump into the skin in the form of heat . Thus, the temperature is maintained at 37°C. To promote these thermal exchanges , the blood vessels dilate. Since they are more voluminous , we are much redder .Anecdotally, many other mammals sweat little or not at all. They have other cooling systems. The elephant uses its bath water and moves its large ears full of blood vessels to release heat from its entire body. The dog, for its part, cools itself with its tongue.
Finally, sweat helps to evacuate impurities , particularly water-soluble impurities, to bring them to the outside of the skin .
So per day, we lose nearly 1/2 liter of water and this can rise to a loss of 3 liters in a few hours during a marathon for example. Hence the need to hydrate well.
h) Sensory receptors
We also find in the dermis more than 2000 sensors per cm2 connected to the brain: some are sensitive to pressure , touch , cold , heat . This helps give us essential information about the outside world, particularly thanks to the hands and fingers which are the most sensitive.
3) 2nd floor: the EPIDERMIS
a) Composition: a brick and cement wall
The epidermis is a set of living cells called keratinocytes organized in the form of bricks to ensure the cohesion of the epidermis . Between these bricks we find a lipid cement which also contributes to the barrier effect. With age, the epidermis becomes thinner and thinner.
b) Mechanism of skin coloring
At the base of the epidermis, we find melanocytes , specialized cells that block part of the sun's radiation by producing melanin pigments . Through this protective mechanism, they are responsible for the color of the skin.
There are two types of melanin : brown pigments and red pigments.
Depending on the skin type, their proportion is different, which determines the color of the skin.
| Skin type | Pigment composition |
| White skin with freckles | Only red pigments which collect in places |
| Clear skin | Balance brown pigments/red pigments |
| Tanned skin | More brown pigments than red pigments |
| Black skin | Only brown pigments distributed throughout the epidermis. No red pigments. |
| Asian skin | Only brown pigments concentrated at the base of the epidermis. The skin then reflects slightly yellow. |
Skin color is the result of a long adaptation to the climate depending on geographical origin. Thus, in the tropics, where the sun is very strong, the trend will be towards black skin for maximum protection against UV rays. Conversely, in more temperate zones, where the sun is less strong, the skin will tend to be lighter . Between the two, there are an infinite number of different skin colors because the blood vessels , more or less visible through transparency, also influence the coloring .
When we expose ourselves to the sun with the aim of getting a tan , we exploit a natural reaction of the body intended to protect us: we stimulate the melanocytes which produce more brown pigments to stop part of the radiation. This colors the skin . But this excess of sun can cause damage because melanin is unable to filter all the sun's rays. Those that do manage to get through can damage our skin cells and cause cancer . There are 80,000 new cases every year and some are fatal . This is why you must protect your skin from childhood by avoiding exposure to the hottest hours and by regularly applying cream, even under a parasol. A food supplement rich in antioxidants (like Absolu Solar by REBORN PARIS) can help stimulate the body's defense mechanisms against harmful radiation.
d) Hyaluronic acid and sensory receptors
Like the dermis, the epidermis also contains hyaluronic acid as well as sensory sensors sensitive to pain.
e) The transformation of the epidermis into the stratum corneum
The epidermis lives and dies and gives rise to the stratum corneum , a layer of dead cells on the surface of the skin . The stages of transformation from one to the other are as follows:
| The birth | The epidermis is made up of cells which transform over the days and are renewed at a regular rate. Thus each cell is born in the basal layer (at the base of the epidermis). |
| Cell division | The cells divide in two and one of the two cells is expelled upwards, which causes the other layers above to move up a notch. |
| The migration | Thus, from division to division, the cells slowly migrate towards the surface. |
| The transformation |
During their journey they transform: 1) Flattening 2) Keratin loading 3) Hardening 4) Creation of bridges between cells |
| The death |
Arriving at the end of their journey to the surface, the cells lose their nucleus and die, which forms the stratum corneum, a chain of dead, flat and hard cells called corneocytes which forms a real protective envelope. |
3) 3rd floor: the HORNED LAYER
The stratum corneum is the protective outer envelope of our skin , a real barrier of a hundredth of a millimeter which separates the body from the external environment. Dotted with small holes called pores , it lets the skin breathe while protecting it. This layer of dead cells from the epidermis is renewed every 3 weeks. Indeed, the cells are inexorably pushed towards the surface by the migrating cells of the epidermis and they end up detaching. This is called the peeling phenomenon. Every day we lose 2 layers of corneocytes and in 70 years our epidermis will have been renewed more than a thousand times with a loss of several kilos of cells .
By using a horsehair glove or exfoliating, you accelerate the epidermal renewal process for real baby skin. Vitamins B9, B12 and D and zinc contribute to cell division to accelerate renewal .
This exceptional skin regeneration ability has been used by researchers to produce skin in the laboratory. They take a few skin cells and culture them in tubes with “lots of good things to eat”. We then witness cell multiplication until pieces of skin are formed. These are very useful for replacing damaged or burned skin . In 3 weeks enough skin can be produced to replace that of a patient burned on more than half of their body. Although unfortunately the aesthetic quality will never be the same as the original skin, it saves lives.
4) 4th floor: the hydrolipidic film
When we put a drop of water on our hand, the drop of water does not spread and does not penetrate the skin , like on an oilcloth. For what ? Because our skin is covered with a virtually invisible fatty film called the hydrolipidic film . The latter plays the role of a protective , resistant and waterproof barrier. Resulting from the mixture between sebum and sweat , this film has a dual purpose. First, it prevents water from entering the body. Fortunately, because otherwise, with each bath we would fill ourselves with water . Secondly, this layer retains water contained in the body thus preventing dehydration .
The presence of this film explains why our fingers wrinkle when we stay in water for too long . As the latter is made up of sweat, soluble in water, upon prolonged contact with the latter, it dissolves. Water can then enter the body and the cells become engorged with liquid. As the skin is very thick on the fingers due to a large number of cells, the phenomenon of deformation is more visible. This change in appearance is fortunately reversible. Indeed, upon leaving the bath , the water evaporates and the hydrolipidic film is reconstituted.
This barrier is essential in the maintenance of our skin microbiota , our “friendly” microbes which prevent pathogenic “enemy” microbes from taking hold. Our dear defenders feed on sebum and sweat to gain strength to go into battle. Be careful not to use stripping soaps which would remove their nourishment and therefore the protection of our skin . Because the acidity of this film , although it slows down the development of certain bacteria to fight against certain diseases, is however not sufficient without our faithful microbe allies.
After this elevator journey through the 5 layers of your skin, it no longer has any secrets for you: you understand it and it is the best way to take care of it. If cosmetics act on the layer of dead cells called the stratum corneum, nutricosmetics will allow a deeper action on the dermis and epidermis, to stimulate your production of hyaluronic acid and collagen, responsible for aging. It will regulate your sebum production, the root cause of pimples. To your gummies ? Ready, fire, go, chew!