What is pH in cosmetics and why is it important for the skin: learning how to adjust it

Many people learned about pH from the well-known advertisement: from it we remember that neutral pH is 5.5. But this is not true at all, and let's understand the terminology. The pH level is an acidity indicator that depends on the concentration level of free hydrogen ions. And its neutral indicator is 6.5-7.5, and pure water is taken as a standard. Anything lower is considered an acidic environment, everything higher is alkaline.

The pH level of healthy skin is acidic

The famous advertisement did not deceive us, although it presented the indicator of the product as a unique feature. The acidity level of the product should be taken into account and adjusted in the production of any cosmetics, and not just expensive and high-quality ones.

So, pH 5.5 - what is behind this indicator? This is the acidity level inherent in healthy skin. However, it can also fluctuate. And it differs by skin type:

• Normal - about 5.5
• Oily - up to 6.0
• Dry - 3.0 - 5.5

However, the pH level on the human body is not uniform. The above indicators concern the skin of the face.

The pH of the scalp usually fluctuates at 4.5-5.5, on the palms and feet - 6.0-6.5, in the décolleté area 5.1-5.5. But for the hair, an even more acidic environment of 4.0 is characteristic.

The main task of the acid mantle of the skin is protective. Such a slightly acidified pH level does not allow harmful microorganisms to multiply on the skin, but for the natural microbiome of the skin, a slightly acidic environment is very favorable. This pH level helps to organize the structure of the lipid layer and ensure a normal level of skin hydration.

What happens when the pH level is disturbed

It is very easy to disturb the acid-base balance of the skin! Even just washing with plain water slightly alkalizes the skin.

However, there is no need to be afraid of this, fluctuations in pH are quite normal and healthy skin is usually able to return to the desired level itself.

But constantly washing with soap, the pH of which fluctuates from 9 to 11, harsh peeling, the pH of which is lost somewhere at level 3, can cause serious harm. If the pH balance of the skin is disturbed, it becomes more sensitive, harmful organisms begin to multiply on its surface, causing inflammation, the level of skin moisture is disturbed, irritation and even allergies, redness and peeling can occur. And it is very possible that constant dry skin is a consequence not of a cream that does not moisturize well, but of an "acidic" or very alkaline cleanser, which daily disrupts the protective layer of the skin.

What should be the pH of cosmetics

Oddly enough, but different: depending on the skin type, area of ​​application and even the type of cosmetic, the pH can fluctuate. When making cosmetics, you need to focus primarily on the skin indicators and the fact that cosmetics should help to balance the acidity level.

• Face cream - from 5 to 5.5, and in the case of oily or dry skin, the pH can be slightly shifted so as to ultimately balance the acidity of the skin: for oily skin, make it a little lower, for dry skin - a little higher.
• Hand and foot cream - 5.5 - 6.0
• Shampoo - 5.0 - 5.5
• Shower gel - 5.5 - 6.0
• Tonic - 4.5-5.5. The acidity level of the tonic is very important. After all, it is the tonic that becomes the final stage of washing and balances the pH of the skin, which after exposure to water and cleansers shifts to the alkaline side.
• Conditioners and rinses for hair - 4.0 - 5.5.

Cosmetics Ingredients and pH

The pH of your cosmetics is, of course, affected by the pH of the ingredients you use in your recipe. Adding acids will obviously lower the pH, while adding more alkaline ingredients will raise the indicators. Even the water you use affects the pH of your cosmetics. Manufacturers of cosmetic ingredients often indicate the acidity level of a 1% solution of the component itself, and you can roughly understand what level of acidity the finished product will have. But sometimes such information is missing, so measuring the pH with a pH meter is a very important step in making your own cosmetics. You can make a cream from the most expensive peptides, but without adjusting the pH, you can get a completely different effect than you expected.

There are a number of components that work only at a certain pH level:

• for example, the well-known niacinamide, which at a pH below 5.5 turns into nicotinic acid (not counting the version of niacinamide from Beurre, it is stable at a pH of 4.0 to 7.0)
• these are any AHA acids that work worse if the pH is too high
• these are some preservatives, for example, the preservative for an acidic environment Euxyl 712, which loses its preservative properties at a pH above 5.5
• the same silk guar very quickly creates a beautiful homogeneous gel in acidified water, and in water with a normal pH of 6.0 - 7.0 you will wait a long time for your solution to turn into a gel. And there are plenty of such examples.

Therefore, share the article on social networks, and when composing recipes for any cosmetics, be sure to pay attention to the pH range in which this or that component works.

How to Measure and Change pH

A special device called a pH meter is used to accurately measure pH. Some also use indicator strips for this, but this is a very inaccurate method, because when measuring the acidity of a cream, you just get a yellow wet piece of paper. Usually, the pH meter is dipped into a cosmetic product and wait until the readings stabilize. If the pH level does not suit you, you can raise or lower it.

Lower pH

Lactic or citric acid is usually used to lower pH. Lactic acid is a milder option, which is preferable for use on the skin. Citric acid can also be used to lower pH in hair cosmetics.

However, it is better to lower pH not with pure acid, but with its solutions. Dilute lactic acid (usually 80% acid is sold everywhere) 1:1 with distilled water, so you will get a 40% lactic acid solution. It is better to make a 10% solution of citric acid: 1 gram of citric acid, 9 grams of water.

Add the solutions 1 drop at a time and mix well, then measure the pH, repeat the procedure until the acidity level reaches the level you need.

Raise the pH level

To increase the pH level, use a 10% solution of L-arginine or NaOH. It is preferable to use L-arginine, since it is not just a means for increasing the pH, but also a good cosmetic asset. To prepare a 10% solution, you need to take 1 gram of L-arginine and 9 grams of distilled water. The pH of such a solution should be slightly higher than 11.

Add the solutions 1 drop at a time and mix well, then measure the pH, repeat the procedure until the acidity level reaches the level you need.

Don't forget to monitor the acidity of your cosmetics. This is a monotonous procedure that will make your cosmetics truly balanced. After all, even the most expensive and effective actives will not give the desired effect if your cream or serum has the wrong pH.

Sources: V. P. Fedotov, V. A. Bocharov, E. Yu. Koretskaya, and others. "Fundamentals of Practical Cosmetology"