What is pH?
As many remember from the school chemistry course and the soap advertising, the pH level is a scale used to specify the acidity or basicity of an aqueous solution.
The very concept of pH appeared about a hundred years ago. It was introduced by the Danish chemist Søren Peder Laurits Sørensen. From Latin, the pH can be translated in two ways: potentia hydrogeni (hydrogen force) or pondus hydrogenii (hydrogen weight).
In any case, the whole story with pH revolves around hydrogen: an alkaline or acidic value determines the concentration level of hydrogen ions in the aqueous solution. For the skin, the pH level is determined based on the hydro-lipid layer.
The pH can be measured in two ways: using an electronic device called a pH meter, or using paper indicators (test strips) - they can be bought at hardware stores and pharmacies. The standard packaging includes one hundred strips, which is enough to determine the acid-base level of all liquid solutions in the house.
The pH level of acids ranges from 6.9 and below, neutral solutions have a pH of around 7.0 and base (alkaline) - from 7.1 and above.
What is the pH of our skin?
The level of pH depends on the body part and the condition of the skin. Therefore, cosmetic products are developed depending on the desired acid-base index for a certain skin type. In healthy people, it varies from 3.0 to 7.0, depending on the body part.
A large number of dermatological problems is associated with a violation of the pH level, and therefore, with changes in the composition of the skin. That's why, when choosing skincare products, it’s worth knowing your skin type and its optimal pH values.
The balanced pH level of the facial skin and most parts of the body is considered to be 5.5. Of course, this value can vary.
In oily skin, the pH is between 4.0 and 5.2, in the normal skin - from 5.2 to 5.7, in the dry skin - from 5.7 to 7.0.
For the feet and palms, the pH is considered to be normal from 6.5 to 7.0, and for the scalp - from 4.5 to 5.5.
In any case, all skincare products (unless they perform special functions) should have an acidic pH. It’s useful for the normalization of the skin condition when it has diseases, during which the pH shifts to an alkaline environment.
Unfortunately, poor nutrition, bad environmental conditions, the use of unsuitable cosmetics, ultraviolet light, diseases of internal organs, disruptions of the endocrine system, the use of certain medications and even just stress – all these can change the healthy pH level of our skin.
What is the pH level of cosmetic products?
The pH of the tap water varies from 6.5 to 8.5, and the use of cleansing products with acidic pH for face washing is almost a necessity. And we don’t mean the normal general soap, of course. Its pH can reach 11.0 which is way too acidic for our facial skin.
Makeup remover and cleansing foams have a pH range from 5.5 to 7.0, face toners range from 4.0 to 5.0, moisturizing serums, creams and sunscreen products range from 5.0 to 6.
Speaking about home-use peelings, cosmetologists don’t recommend using the products with pH below 3.5 at home.
Optimal pH level of shower gel and body creams is from 5.8 to 6.0. Exceptions are hand creams, their pH level should be around 6.3, legs – pH level around 6.9 and breast moisturizers – pH level around 5.1.
What's wrong with acid peels?
Despite all our love for chemical peelings, dermatologists agree that the correct use of products with a pH below 3.5 is possible only in the cosmetology room. With an increase in the acid-base balance, the irritating potential for the skin is greatly elevated.
There is an opinion that acids work only at a low pH level (less than 3.5), but this is misleading. If we are talking about the professional procedures performed by a cosmetologist under strict control with the obligatory subsequent use of the neutralizer, the pH of such peels may indeed be below 3.5. But for home procedures, low pH is very undesirable and even dangerous. A pH below 3.5 irritates the free nerve endings (C-fibers) in the epidermis of the skin, which in light cases is felt like itching, tingling and burning, and in severe cases, if the acid isn’t neutralized, provokes an inflammatory reaction of the skin. The lower the pH, the higher the likelihood of such inflammation. This doesn’t mean that acid peels can’t be used at home. To avoid negative effects on the skin, but to maintain effective exfoliating and renewing properties of acids, the pH in the home peelings is artificially increased - this is done by introducing a special buffer substance into the formula. Thus, the irritating properties of acids are reduced while maintaining their sufficient effectiveness.
Most acid peels available for sale have a pH level of 4.0 to 5.0 and are safe to use.
What about Alkaline Cosmetics?
Cosmetic products with alkaline pH level are prescribed to people with psoriasis treatment. With this disease, the pH of the skin shifts to the acidic side.
However, recently, the so-called alkaline skincare is becoming more popular among the general audience. Specialists treat these products with distrust. According to manufacturers, alkaline agents are organically absorbed by the skin. They provide examples of the skin of infants and the pH of amniotic fluid, which is within 8.0-8.5. However, there are no serious experimental results on the positive effects of alkaline cosmetics on the healthy skin of adults. Even the opposite, there are documented studies confirming that the loss of moisture is much higher when skin is exposed to alkaline products with a pH of 8.0, compared to using cosmetics with a pH of 3.5 to 5.0.
The pH value in hair care products
Since the pH level can be determined for liquid substances only, the term "pH of the hair" is very conditional. The surface of the hair has the pH that we comb from the hydrolipid layer of the skin, and its healthy value is in the range of 4.5-5.5. Acid-base balance of hair above this level is considered unhealthy, and at pH above 8.5, any chemical procedures are prohibited.
By the way, chemical procedures (using products for hair dyeing and hair straightening) are the most common reasons for the shift of the pH level of the hair to the alkaline side. All these chemical reactions happen inside the hair and partially or completely change its structure.
After hair bleaching and dying, it is advisable to use shampoos with a pH level below 5 on the day of the procedure, to restore the pH of the scalp and hair.
All products for home hair care have an acidic pH. Shampoos - a little higher, and treatment products for opening the cuticle, masks, balms and styling products - lower. For severely damaged hair, you can safely use the products with a pH of 4.5 to 5.0.
In addition to chemical effects on the hair, there are other factors that affect the pH level - these are fungal and bacterial head skin infections. With their presence, the pH of the hair and scalp is higher than 7.0, which creates a favorable environment for the reproduction of bacteria.
By now, you should hopefully be intrigued about the pH level of your favorite K-Beauty products, right? We have fantastic news! The users of the Reddit thread AsianBeauty created a spreadsheet with the information about all popular Korean skincare products, and they keep it updated! Check your products here: the pH level of K-Beauty
- Korean Kiwi Beauty