Acidity plays a key role for the skin. Some enzymes in the stratum corneum are activated in an acidic environment. Changes in pH affect the activity of enzymes and affect the normal process of skin exfoliation (desquamation), so maintaining the correct pH of the skin is essential for its healthy and blooming appearance.
In addition, the acidic pH inhibits the growth of some harmful bacteria on the skin.

What is pH?
pH is a measure of acidity and alkalinity. The pH scale ranges from 0 to 14, with 7 being neutral (neither acidic nor alkaline). Anything below 7 is acid. A solution with a pH above 7 is alkaline.

Water soluble pH
· Lemon juice pH 2.0
· Vinegar pH 3.0
· Water pH 7.0 (neutral)
· Baking soda pH 8.0
· Soap pH 8.0-11.0
· Ammonia pH 12.0

Acid mantle skin
The reliability and strength of the epidermal barrier helps to maintain the hydrolipidic mantle of the skin.
This is a film on the surface of the skin, consisting of fat, sweat and acids formed as a result of the vital activity of the epidermis. If it is damaged or removed, the skin will no longer be able to resist microorganisms (such as bacteria), strong chemicals, and harmful substances. Water balance skin will be broken!

Why is it important to know the pH of skin care products?
A constant change in the pH of the skin is harmful because it leads to the destruction of the protective layer, which performs an important protective function. An exception would be a specific purpose, such as an alpha hydroxy acid (AHA) treatment or exfoliation.

Higher (alkaline) pH products expand the follicles, which significantly increases skin permeability. Damaged skin is more vulnerable to microorganisms and irritants.

What you need to know about pH:
· Extreme pH levels damage the skin and cause inflammation, irritation and dryness.
· Recycled products that are not pH balanced can lead to chronic problems for your skin.

You can test the pH of your products yourself
You can test the pH of your skin care products with a litmus strip or purchase a pH meter.

If pH less than 4 or more than 6 you should seriously think about stop using this product. The use of such a product is not necessary for sensitive and normal skin, but if your skin is problematic, acne is present, then the use of an acidic agent (not lower than 3 pH) from one to three times a week is possible.

Don't forget to check your makeup products too. Decorative products should be like the pH of your skin.

1 pH difference matters
It would seem that a difference of 1 pH is not much. According to the pH scale, the difference in 1 digit is 10.
It means that pH 4 is 10 times more acidic, than pH 5.
A pH 3 is 100 times more acidic than pH 5, pH 2 is 1000 times more acidic than pH 5. (The pH scale is logarithmic, not linear!)

Soap!
The most commonly used cleaning product is soap. But body soap is alkaline, its pH is usually 8.0-11.0. Harsh alkaline environment that is not suitable for your face (5.5). Thus, it is impossible to use one remedy for cleansing the body and face! Look for a neutral label (facial soap) on the packaging, or the packaging should state that it is suitable for the face and body.

Skin microflora– beneficial microorganisms, our constant “cohabitants” are perfectly adapted to their native environment and help maintain biological stability, skin cleanliness and protect it from pathogenic microorganisms. How is the system of protection of our skin and body as a whole arranged?

The microflora of healthy skin is an ecosystem that is quite resistant to external influences. Human skin microflora largely regulated by the acidity (pH) of the skin. An acidic pH is one of the main factors that make the skin “unattractive” to bacteria. Typically, the skin temperature is slightly below normal body temperature, its surface is slightly acidic and mostly dry, while for most bacteria, neutral pH, a temperature of 33 ° C and high humidity are optimal for reproduction.

In general, skin antimicrobial protection includes mechanical rigidity (stability) of the stratum corneum of the epidermis, reduced moisture content, lipids of the stratum corneum, lysozyme, pH 5. The fact that the normal pH of the skin surface plays a beneficial role in relation to local immunity is now considered undeniable.

Acidity and microflora of the skin

A popular theory is that skin acidity(pH) plays an important role in its antimicrobial protection. The normal state of the skin is acidic, it is maintained by the secretion of sweat glands, sebum and the breakdown of fatty acids by Staphylococcus epidermidis. Therefore, it is believed that the resident microflora of the skin (i.e. normoflora) also partially maintains the acidic pH of the skin.

Normal (resident) flora grows best at an acidic pH, while pathogenic bacteria, such as Staphylococcus aureus, prefer a neutral pH. Thus, a more acidic pH protects the skin from colonization by non-resident and pathogenic bacteria.

The acids produced by the resident microflora (normoflora) are also part of the local defense mechanisms and depend on the normal microflora. For example, Staphylococcus epidermidis, Propionibacterium acnes, Pityrosporum ovale, Corynebacteria produce specific lipase and esterase enzymes that break down triglycerides into free fatty acids - this leads to a decrease in the pH of the skin surface and thus creates unfavorable conditions for pathogenic microorganisms that a person comes into contact with daily.

The normal flora also acts as a barrier and serves to prevent invasion and growth of pathogenic bacteria. Healthy growth and retention of resident flora effectively prevents colonization of the skin by transient bacteria, including – Escherichia coli(Escherichia coli) Pseudomonas, Staphylococcus aureus(Staphylococcus aureus), candida albicans.

Us and "them": a map of the skin microflora

The microflora of the skin of the face differs, say, from the flora of the hands or other parts of the body. The composition of bacterial strains on the skin varies depending on the area of ​​the skin (table). The table below shows a kind of map of the human skin microflora, where you can see that each part of the body is characterized by a certain type of microorganisms.

A high density of bacteria is found in areas of the skin with a less acidic pH: genitals, anus, folds under the mammary glands, armpits. Relatively dry and exposed areas of the skin have a lower pH and a lower density of microorganisms. For example, the inner surface of the forearms has a bacterial population (in colony forming units) of 102-103 cfu/cm2 - compared to 105 cfu/cm2 in the armpits.

Artificial occlusion (wrapping) of the forearm leads to a significant change in skin pH, composition and density of bacterial strains. For example, in one study, before occlusion, skin pH was 4.38, but after 5 days of occlusion it increased to 7.05. Similarly, in the case where the bacterial count before occlusion was 1.8 x 102 cfu/cm 2 , it increased to 4.5 x 106 cm 2 after 5 days of occlusion. It follows that the moist environment of the skin promotes bacterial growth and colonization. In the folds of the skin, where the pH is slightly higher, there is an increased density of bacteria.

Normal skin microflora: acidic pH - stability

As already mentioned, the acidity of the skin surface affects the growth of both permanent and pathogenic microorganisms. The presence of an acidic shell is one of the key factors in skin immunity. Conversely, pH fluctuations disrupt the quantitative and qualitative composition of the normoflora and can become a predisposing factor for the development of dermatological pathologies.

• The acidic pH of the skin (pH 4.0-4.5) helps the resident bacterial flora to remain in a certain physiological zone in a stable amount and prevents the settlement of pathogenic microorganisms.
• Alkaline pH (8.9), on the contrary, contributes to the dispersion of permanent microflora over the skin.
• A less acidic pH favors the growth of microorganisms, especially gram-negative and propionic bacteria.
• High pH in the axillary folds promotes accelerated bacterial growth, which is associated with the development of an unpleasant odor.
• An acidic pH increases the activity of antibacterial lipids and peptides. The acidic pH of the skin facilitates the production of natural antimicrobial peptides, promotes and regulates keratinization and desquamation.
• The normal microflora of human skin is also a source of antibacterial components (proteins, lipids, peptides). For example, bacteriocins are a group of specific proteins produced by bacteria of the genus Staphylococcus epidermidis: bacteriocin is partially active against other staphylococci, it is especially effective in inhibiting growth Staphylococcus aureus.

Relationship of pH, microflora with skin pathologies

Changes in skin pH and other organic factors play a role in the pathogenesis of a number of skin pathologies, in their prevention and treatment.

acne

Propionibacterium acnes, which are associated with acne, are a classic example of how a slight increase in skin pH facilitates the transition of a resident bacterium into a pathogenic one. At normal pH 5.5 growth Propionibacterium acnes is minimal, however, a slight shift to the alkaline side makes the environment more comfortable for these microorganisms, resulting in growth Propionibacterium acnes is rapidly intensifying.

Recent studies have shown the consequences of skin pH changes in atopic dermatitis, especially skin barrier dysfunction and increased colonization. Staphylococcus aureus. The same thing happens with atopic eczema, in addition, not only increases growth Staphylococcus aureus, but also the production of exotoxin, which can induce the spread of eczema to other, more distant areas.

Candidiasis

A change in skin pH from acidic to alkaline is also a risk factor for developing a fungal infection (). An interesting study in which a suspension of candida albicans and occluded for 24 hours. It has been shown that more pronounced inflammatory phenomena occur at high pH. This proves that the pH level is associated with local immunity - the ability of the skin to defend itself against infections. These data allow us to conclude that a change in skin acidity is a risk factor for the development of candidiasis (thrush).

Hygiene and care: in harmony with the microflora

Height Brevibacterium epidermidis with which they are associated bad smell body, can only be slowed down if the pH is lowered to 5.0 or lower. It is noteworthy that washing with tap water with a pH of about 8.0 can increase the acidity of the skin and keep it in this state for up to 6 hours. At the same time, daily bathing for several weeks or stopping washing for the same period of time did not lead to overgrowth pathogenic flora or to a significant imbalance in the composition of friendly bacteria.

The use of synthetic detergents with an acidity similar to the skin surface resulted in an increase in the pH of the skin surface for a short time, and these changes were limited to the superficial layers of the stratum corneum.

It is important to understand that the regular use of alkaline cleansers (milk, tonic, especially soap), detergents that damage normal flora, and even “hard” alkaline water (pH 8.0) will adversely affect the natural pH of the skin and disrupt its microflora. To maintain the microflora of the skin of the face and body, it is necessary to use cosmetics and care products that do not violate the normal pH of the skin.

Hi all!

I invite you to Friday "talk" :)

What is skin pH? Do you pay attention to the funds aimed at balancing the acid-base balance? And how to choose the right care, guided by knowledge of the pH of your skin?

We all dream to find effective means for facial skin care, which will immediately solve all our problems. We read various forums and reviews, try to figure out intricate compositions, translate tons of samplers in search of the one that suits us.

Have you ever faced a situation where a product that seems to suit everyone, on which a lot of laudatory reviews have been written, does not work exactly on your skin so perfectly? Or even worse - provokes redness, rashes or peeling?

Lately, I've been seeing more and more skin care recommendations based on pH.
In annotations and posts about skincare products, we often come across the following phrases: “neutral pH”, “pH balanced”, “restores skin pH”, “skin pH identical”, “maintains skin pH balance”, “regulates pH, etc.
But when I try to understand and read literature, I get more and more confused.

The abbreviation pH is used to denote the ratio of acid to base and is measured on a scale of 0 to 14.

On the surface of the skin of the face there is a thin hydrolipidic film that makes up the protective layer of the epidermis, with the help of which the body resists external influences: dirt, infections, dry air, etc. Scientists have proven that the pH of the protective layer of the skin, as a rule, is acidic, and fluctuates in the pH range of 4-7 - it is in such an environment that the usual skin microflora is able to exist normally, releasing certain substances that prevent the colonization of the skin by pathogenic bacteria that prefer a higher level. pH.

There are many factors that affect the pH level of the skin, from our diet to the way we wash our face with water. Normal PH is considered to be an indicator of 5.5 - this is the boundary state between an alkaline and acidic environment. If the PH level is above or below this figure, then this indicates skin problems. The prevalence of an acidic environment is expressed in a decrease in the indicator: PH-balance from 3 to 5.5 is typical for oily skin. If the indicators are above the neutral value, then the alkaline environment takes over and the skin becomes dry.

That is, we can conclude that even with daily washing (pH of water fluctuates around 7), we are already injuring the skin, and if normal skin it takes several hours to restore its original pH level, dry or oily skin is more difficult to do this. Therefore, it is important to choose the right care (not only washing, but also the subsequent stages) based on the needs of our skin in order to help it in its daily struggle with negative factors.

And here a logical question arises: what to do to even out the pH balance of the skin and make it perfect? How to choose care in such a way that it does not harm, and even helps?

Some articles strongly recommend using pH balancers labeled 5.5. Others suggest maintaining the existing pH level in comfortable conditions and using, for example, products with a more acidic composition for oily skin and, conversely, more alkaline for dry skin. Still others argue that you need to strive to restore the level by choosing the opposite skin pH product.

Many bloggers generally advise combining skin care products with different acid-base indicators for the skin, for example, according to the following scheme: choose cleansers and tonics that are as close as possible to the pH of the skin, that is, more acidic (with acids in the composition) or neutral (balanced pH = 5.5), and for balance, choose moisturizing serums and creams.

What do you think about it? Do you think it is necessary to be guided by the pH level of the skin when choosing facial products? Do you pay attention to the "neutral pH" label? And how to choose the right products based on the pH of the skin?

Perhaps my question is very basic and will seem quite simple to someone, but I would really like to know not only the opinion of experts and people who understand, but also those who choose their own daily care.

P.S. I beg you not to swear in the comments. Please, let's discuss the issue as honestly as possible.

The mysterious abbreviation "PH" means acid-base balance. The health of the skin directly depends on its level. The lipid layer on the surface of the dermis has certain indicators of acid-base balance. Normal PH is considered to be an indicator of 5.5 - this is the borderline state between an alkaline and acidic environment. If the PH level is above or below this figure, then this indicates skin problems. The prevalence of an acidic environment is expressed in a decrease in the indicator: PH balance from 3 to 5.5 is typical for dry skin. If the indicators are above the neutral value, then the alkaline environment takes over and the skin becomes oily.

Changes in the level of PH-balance leads to unpleasant consequences. The prevalence of an alkaline environment causes an increase in the number of bacteria on the surface of the skin, which, in turn, provokes the appearance of inflammation, acne and various dermatitis. Under the influence of alkali, the pores become enlarged. The tone of the skin is also significantly reduced, which makes it look dull.
A decrease in the PH balance leads to a significant loss of moisture, as a result of which the skin is put dry, cracked, peeling and redness appear on it.

Optimal for the skin is a slightly acidic environment, which is expressed in the cherished figure of 5.5. It is with this value of PH-balance that the skin can independently cope with bacteria and maintain the necessary level of moisture.
The level of acid-base balance can change under the influence of several factors. In order for the skin to be healthy, it is not enough to use good cosmetics. It is important to take comprehensive care of the skin.

So, let's see what factors can affect the PH balance.

Nutrition.
Nutrition directly affects not only your weight, but also the condition of the skin. The abuse of sweets leads to a shift in the PH balance towards an acidic environment. If you notice that your skin has become dry and shows signs of peeling, the first thing to do is to eliminate sweets and cakes from your diet.

Abuse of spicy and canned food can lead to a decrease in PH values. Acne sufferers need to seriously consider rethinking their daily menu.

solar radiation.
Fans of uncontrolled tanning can face unpleasant consequences for the skin, since the sun's rays can change the pH balance towards an alkaline environment. Have you noticed that after a few hours under the scorching sun, your skin feels dry and tight? All this is the result of a violation of the neutral level of acid-base balance. Therefore, experts strongly recommend not to sunbathe without.

And remember: the sun's rays are most active during the day, so this time is best spent not on the beach. If you care about your skin, then choose morning and evening hours for sunbathing.

Age.
Unfortunately, with age, the level of PH-balance changes significantly towards an alkaline environment. Therefore, after 40 years, almost everyone observes some changes in the skin: it becomes dull and flabby, fine wrinkles appear, pores expand.

It is important to know about this age feature and take it into account when choosing.

Care.
To maintain an optimal PH balance, it is important to learn how to properly cleanse the skin. washing hot water very bad for the skin. You need to wash yourself with cool water with special products. It is better to refuse soap, because even those brands that are marked “PH - 5.5” change the ratio to the alkaline side. True, healthy skin quickly restores its natural balance even after washing with soap, but if your skin already has low PH values, this procedure can aggravate the situation.

It is important to remember that from proper care directly depends on the level of acid-base balance of the skin. Bad Choice cosmetics can lead to changes in the environment of the skin. Creams and tonics must be chosen, taking into account the characteristics of the dermis. The use of products that are not intended for your skin type can significantly worsen its condition.
Care must be taken with special products, which include special active substances. Their uncontrolled use can upset the PH balance.

For example, funds lines for problematic skin often contain various acids. These substances are quite aggressive and, if used excessively, can change the acid-base balance. As a result, the skin begins to peel off. Therefore, if you are faced with inflammation and acne, you should not self-medicate and try to apply as often as possible. special means. This approach will not solve the problem, but only exacerbate it. It is better to contact a specialist who will select an individual care for you.

The process of formation of keratin, melanin and PH of the skin.
This complex process begins in the germinal layer and ends in the stratum corneum, where cells undergo numerous changes. Their cytoplasm and nucleus atrophy. Keratohyamine, produced in the granular layer, is responsible for the formation of sebum. In the transparent layer, where living epithelial cells approach the final period of "living" existence, keratohyamine is intensively replaced by keratin. At this level, the cells are almost completely dehydrated. Dehydration is accompanied by the process of keratinization. The stratum corneum contains about 10% water, compared to 70-72% water in the germinal and papillary layers. The formation of keratin is controlled by the activity of many endocrine glands that secrete hormones. For example, increasing the level of female hormones reduces the formation of keratin. Some other hormones, on the contrary, accelerate the formation of keratin.

The formation of melanin. Melanin is a high energy pigment. It is formed from many special cells located in the basal-germ layer, known as melanocytes. The formation and distribution of melanolin is influenced by external and internal factors. The melanin grains concentrated in the basal layer are then transferred to the outer layers of the epidermis. Under the influence of appropriate stimuli, such as solar training, they affect the color of the skin. Thus, sunbathing leads to the activation of pigment cells, in which, under the influence of sunlight melanin is actively released. As a result, the skin acquires a swarthy, darker color. An active pH reaction of liquids or creams indicates their acidity or alkalinity. The pH scale contains values ​​from 0 to 14, neutral pH corresponds to 7. Acidity is any value below 7. A decrease in pH indicates an increase in acidity. Acidity is characterized by a sour taste, such as that of a lemon. Alkalinity is an alkaline reaction that corresponds to pH values ​​from 7 to 14. Increasing the pH increases the degree of alkalinity. Alkalis belong to a number of compounds that, when exposed to acids, can increase salts, turn red litmus blue, and have the ability to wash away fats. Neutrality. Neutral solution is a soft, chemically inactive solution, i.e. neither alkaline nor acidic. Although a neutral reaction corresponds to a value of 7 on a scale, the concept of "neutrality" is broader and implies a pH of 6.5 to 7.5 pH of the skin and its cover (mantle). The secrets of the sebaceous and sweat glands and the formation of keratin in the epidermis form an "acid mantle" that protects the skin from bacteria and dehydration, and also helps to maintain its normal condition.

Physiologically, the acidity pH of the skin tissue can vary significantly. The pH of the skin, being exposed to external factors such as solar radiation, the influence of cosmetics, as well as in severe physical form, affects the pH value. This indicator varies in different parts of the body. The pH of the inner layers of the skin corresponds to the pH of the blood and plasma, i.e. approximately 7.35, while in the outer layers of the epidermis, the pH ranges from 4.8 to 5. The pH of the stratum corneum of healthy skin is 5-5.6.

When caring for the skin, we should take care of the cover of the "acid mantle". Special attention should be referred to Various types skin - oily skin has a pH in the range of 7.5-8, dry skin has a pH of about 6.5. For oily skin, products with an alkaline reaction are desirable, while for dry skin, products with a slightly acidic environment are needed.

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