Not sour: What is the pH level in cosmetics and why know it
Text: Daria Burkova
What to know about the pH level in cosmetics Useless and sometimes very necessary, you probably have heard more than once. We understand the intricacies of this statement: what is pH, what happens from a violation of its level, how to maintain a balance and whether the "magic 5.5" work.
What is pH?
As many remember from the school course of chemistry and advertising Dove soap, the pH level characterizes acidic (from 6.9 and below), neutral (7.0) or alkaline environment (from 7.1 and above). The concept of pH itself appeared about a hundred years ago - in 1909 it was introduced by the Danish chemist Sören Peder Lauritz Sørensen. He is considered the founder of modern pH-metry. At Latin, the pH can be deciphered in two ways: potentia hydrogeni (hydrogen power) or pondus hydrogenii (hydrogen weight). In any case, the whole history of pH revolves around hydrogen: alkaline or acid indicators determine the level of hydrogen ion concentration in an aqueous solution. For skin, the pH level is determined by the lipid layer.
The pH level can be set in two ways: using an electronic device called a pH meter, or using paper indicators (test strips) —you can buy them at hardware stores, pet stores and pharmacies. The standard package includes one hundred strips, which is enough to determine the acid-base level of all liquid solutions in the house. To determine the pH of the means "by eye" on the composition or sensations on the skin is not only difficult, but not always possible. "If the cosmetic product has AHA-acids (for example, glycolic, lactic or citric), its pH, of course, will be more shifted to the acidic side, but it will not always be possible to determine from the sensations when using, if the concentration of acids is low," says Elena Kuznitskaya, a leading beautician brands EviDenS de Beauté and Perricone MD.
What is pH
The pH levels of the skin in different parts of the body and with its different condition are different, therefore, cosmetics are developed depending on the desired acid-base indicator in one or another area of the body - in healthy people it varies from 3.0 to 7.0. “A large number of dermatological problems are associated precisely with a violation of the pH level, and therefore, with changes in the composition of the skin. That’s why choosing care products you should know about your skin type and optimal pH values in one or another area,” says Elena Temirgaliyeva , the creator of the line of cosmetics for body care SB-26.
A pH level of 5.5 is considered to be a balanced pH of the face and most of the body. Of course, this value may vary. For oily skin, the pH is in the range from 4.0 to 5.2, for normal skin - from 5.2 to 5.7, for dry skin - from 5.7 to 7.0. For the feet and palms, a pH of between 6.5 and 7.0 is considered normal, and for the scalp, between 4.5 and 5.5. Accordingly, knowing your skin type and its pH level, you can choose the best care products by testing them in advance. In any case, all cosmetics for skin care of the body, face and head, if it does not perform certain special functions, should be acidic pH. It is also useful for normalizing the condition of the skin in various diseases, during which the pH shifts to an alkaline environment: with acne, to 7.0, with eczema, to 6.5, and with fungal diseases, to 6.0. "This can occur under the influence of various factors. Both due to poor nutrition, unfavorable environmental conditions, the use of improper cosmetics, exposure to ultraviolet radiation, and due to diseases of internal organs, endocrine system malfunction, the use of drugs and even stress." Elena Temirgaliyeva.
The pH of tap water ranges from 6.5 to 8.5, so the use of washing and washing products with acidic pH is almost a must. Of course, ordinary soap does not belong to such products - its pH can reach 11.0. For the shower gel and body cream, the pH is considered optimal from 5.8 to 6.0. The exceptions are hand creams (about 6.3), legs (about 6.9) and breasts (about 5.1). For make-up removers and washing gels, pH ranges from 5.5 to 7.0, for face toners from 4.0 to 5.0, for moisturizing serums, creams and sunscreens from 5.0 to 6 , 0. An interesting situation is obtained with home peels: cosmetologists do not recommend using products with a pH below 3.5 on their own.
What is wrong with acid peels
Alas, with all our love of skin chemical exfoliation, dermatologists agree that the correct use of products with a pH below 3.5 is possible only in the cosmetology office, because with a decrease in acid-base balance to this indicator the irritating potential for the skin greatly increases. "There is an opinion that acids work only at low pH (less than 3.5), but this is a delusion. If we are talking about professional procedures that a cosmetologist conducts under strict control with the obligatory subsequent use of a tonic neutralizer, then the pH of such peelings can really to be below 3.5. But for home procedures, low pH is very undesirable and even dangerous. The pH level below 3.5 irritates the free nerve endings (C-fibers) in the skin epidermis, which in mild cases is felt as itching, tingling and burning , and in heavy x, if the acid cannot be neutralized, it provokes an inflammatory skin reaction. The lower the pH, the higher the likelihood of such inflammation. This does not mean that acid peels cannot be used at home. To avoid negative effects on the skin, but to preserve the effective peeling and renewing properties of acids, The pH in home peels is artificially high — this is done by introducing a special substance-buffer into the formula. Thus, the irritating properties of the acids are reduced while maintaining their sufficient effectiveness. ” Anastasia Malenkina Chaldeans, Head of Product Development Natura Siberica.
Of course, artificially overestimating the pH of acid peels for home use, companies are also trying to protect themselves. Illiterate use of products with low pH can really have a variety of consequences. Most of the acid peels available for free sale have a pH level from 4.0 to 5.0, but experts do not recommend using them on a regular basis and advise you to know the extent to exfoliating the skin. "For healthy skin, long-term use of cosmetics with a low acid pH is not desirable. For enzyme systems of the stratum corneum, the pH level of 5.4-5.5 is most favorable. With a long-term rejection in one direction or another, the enzyme activity decreases, which means that recovery the stratum corneum is inhibited, its protective functions are reduced, "says Elena Kuznitskaya.
Why do you need alkaline cosmetics
Doctors prescribe alkaline pH cosmetics to patients for the treatment of psoriasis, because with this disease the pH of the skin shifts to the acidic side - and this is a separate medical history. But lately, the so-called alkaline cosmetics has become popular. Experts treat it with suspicion. "According to manufacturers, alkaline products are organically perceived by the skin. The skin of infants and the pH of the amniotic fluid, which is in the range of 8.0-8.5, are given as an example. But so far no serious experimentally confirmed results of the positive effects of alkaline cosmetics on healthy skin of adults are presented But there are documented studies confirming that when exposed to an alkaline product with a pH of 8.0, transdermal moisture loss is much higher than when using cosmetics with a pH of 3.5 to 5.0 ", says Helen Kuznitskaya.
PH value in hair care cosmetics
Since the pH level is determined only for liquid substances, such a concept as "hair pH" is rather arbitrary. The surface of the hair has the pH that we comb from the lipid layer of the skin, and its healthy value is in the range of 4.5-5.5. Acid-alkaline balance of hair above this level is considered unhealthy, and at pH above 8.5, any chemical procedures are prohibited. By the way, first of all it is they who shift the pH of the hair to the alkaline side. "Alkaline products include hair dye products, their curls and straightening. All these chemical reactions take place inside the hair and partially or completely change its structure. Since it is rather difficult to penetrate the basis of natural hair, it is difficult to penetrate the cuticular layers into these compositions add alkaline components, ”says Elvira Sachkova, technologist of the brand Redken.“ It is worth highlighting decolorizing powders, pastes and oils into a separate group of alkaline compounds in terms of pH. This group of strong clarification It has a high alkalinity level of around 11.0-12.0. After bleaching, permanent dyeing, chemistry, it is advisable to use shampoos with a pH below 5.0 ”to restore the pH of the scalp and hair on the day of dyeing.
All home care products have an acidic pH. Shampoos - a little higher, products for disclosing cuticles, masks, balms and styling products - lower. For heavily damaged hair, you can safely take all the tools with a pH from 4.5 to 5.0. In addition to the chemical effects on the hair, there are other factors that affect the change in pH, such as fungal and bacterial infections of the scalp. If available, the pH of the hair and scalp is above 7.0, which creates a favorable environment for the growth of bacteria. Also, special attention to maintaining the correct acidic environment (4.5-5.5) should be paid to those who have curly hair: their cuticle is constantly open.
Photo: Sephora (1, 2), Organic Shop, Redken, Hair Product, Iles Formula, Aizel, Style Story, Cult Beauty