A combination of words “acid” and “facial skincare” can sound very scary, especially if you remember the pieces of metal dissolving in a test tube with hydrochloric acid from chemistry lessons. However, very different acids are used in cosmetology, and FDA studies conducted over several decades have proved that the use of certain acids on the skin is absolutely safe.
In the context of facial care, acids are primarily associated with exfoliation and deep peeling, but in fact, their effect is much wider. In addition to acid-exfoliates, there are acids that retain water in the skin. The famous hyaluronic acid, which can be found in many moisturizers, is just that type of acid that doesn’t have exfoliating properties, but it is capable of retaining water in the skin.
Why you need to exfoliate the skin
Millions of cells die daily on the surface of your skin, and this process could be intensified by the action of solar radiation, genetics, or specific diseases. When keratinized cells accumulate too much, they lead to dull, uneven complexion, fine wrinkles, peeling and clogged pores. These and other related problems can be solved by regular exfoliation - mechanical or chemical. The mechanical method consists in removing the upper keratinized layer of the skin with the help of abrasive products: scrubs, peelings, or brushes. Chemical exfoliation involves the use of products with acids that remove dead skin cells and significantly improve skin condition and at the same time help skincare to work more effectively.
Nowadays, dermatologists are increasingly advising to give preference to the second option – chemical exfoliation. "Scrubs or brushes only work in the uppermost layer of the skin and give a weak and short-term effect," explains Rita Lee, biochemist, and author of “Just About Skin”, the blog about skin care. "Mechanical peeling is more traumatic, superficial, and doesn’t have such a therapeutic effect as the chemical peeling," says cosmetician Sali Kardava. - Acid peeling is a therapeutic procedure, it provides deeper cleansing, suppresses the activity of sebaceous sweat glands, removes hyperpigmentation from post-acne and photoaging, reduces pores and gives deep hydration. "
What problems are solved by different acids
All the exfoliating acids work on the same principle: they dissolve the dead cells of the epidermis and help the skin to get rid of them faster, making room for the new ones. In the simplest approximation, acidic peeling is a controlled skin damage, aimed at leveling skin relief and renewal. Due to their properties, hydroxy acids help moisturizing components of other ingredients work more efficiently and penetrate deeper into the epidermis. Currently, three subclasses of acids are used in cosmetology: alpha-hydroxy-, beta-hydroxy- and polyhydroxy acids.
AHA acids are extracted from plants and milk, but most of the acids used in cosmetology are artificially synthesized in laboratories. "In low concentrations - up to 4% - alpha acids are able to retain water in the epidermis, and in higher - from 5% or higher - act as exfoliants," explains the world expert in cosmetology and the creator of Beautypedia, Paul Begun.
AHA acids are water soluble, they can’t penetrate deeply into the skin, but work well on its surface and stimulate skin renewal. Alpha hydroxy acids are most effective in combating the signs of photoaging, such as wrinkles, pigmentation, loss of elasticity, radiance, firmness, and also with post-acne traces. They contribute to the production of collagen and elastin, which is especially important for aging skin.
The most common exfoliating ingredient of all price categories is glycolic acid. This is a cheaper ingredient, obtained from sugar cane, but it is also one of the most effective. A study of dermatologists from Wakayama Medical University has proved that the use of salon peelings with high concentrations of glycolic acid is extremely effective in treating complex forms of acne. It also increases the level of skin hydration and the content of skin collagen. The second popular acid is lactic acid, and it could be found in all dairy products. Do you remember the legend about Cleopatra and a hundred mares? This is it. This acid, as well as glycolic acid, has exfoliating, anti-aging properties and helps fight the signs of photoaging of the skin. By the degree of effectiveness, lactic and glycolic acids are approximately the same.
As part of skincare products, citric acid is also very common. In most cases it isn’t used as an exfoliating component, but as a preservative or acidity regulator and is indicated at the very end of the ingredients list. At the same time, its restoring and renewing properties are similar in many respects to glycolic acid. A much less common ingredient is mandelic acid. Dermatologists recommend it for people with sensitive skin, as it is less aggressive, but at the same time gives a weaker exfoliating effect. The action of malic and tartaric acids is least studied, they are mainly used as preservatives and acidity regulators. However, dermatologists from the American Institute of Aesthetic Medicine Gateway have proven the effectiveness of malic acid against hyperpigmentation.
The newest generation of AHA acids are polyhydroxy acids, they are also often recommended for people with sensitive skin and suffering from atopic dermatitis. "Compared to alpha hydroxy acids, polyhydroxy acids (PHA) has a milder effect on the skin and, as a rule, doesn’t cause irritation," says cosmetician Sali Kardava. - Such non-aggressive action of polyhydroxy acids can be explained by the high molecular weight. Large molecules penetrate the skin more slowly and don’t cause irritation. In clinical trials, it has also been proven that PHA can prevent skin aging."
Polyhydroxy acids include gluconic acid, which is a natural component of the skin, and its use stimulates the production of elastin, which is especially useful for skin aging. Polyhydroxy acids also enhance the protective functions of the skin and, unlike other acids, don’t increase its photosensitivity. Moreover, a study of the employees of the Pennsylvania College of Optometry has shown that gluconic acid is capable of blocking up to 50% of ultraviolet radiation.
Another group of acids is BHA or beta-hydroxy acids. They differ from alpha hydroxy acids and they are dissolved in fat, not water. These acids are able to penetrate deep into the pores, clean them from the inside, dissolve black dots, and generally have a beneficial effect on acne prone skin. There are several types of BHA-acids, but the most common one is salicylic acid. In its pure form, salicylic acid has a disinfecting and anti-inflammatory effect, often prescribed to people with coarse oily skin, suffering from rashes. However, it’s also an excellent exfoliating remedy and, like AHA acids, it struggles with signs of photoaging of any skin type.
Can acids harm
The effectiveness of hydroxy acids is determined primarily by their concentration and the time spent on the skin. AHA acids in cosmetics for home care often have a concentration of 5 to 15%, and salicylic - 0.5-2% by volume. Responsible manufacturers, as a rule, indicate the concentration of acids on the package of products, but if there is no special label, then one can follow the simple rule: the closer to the top of the list of ingredients, the higher its concentration.
Keep in mind that two products with the same concentration can (and will most likely) work differently. It also depends on other ingredients contained in the product and what their level of acidity is. For example, the US Food and Drug Administration (FDA) recommends choosing products with a pH above 3.5, but manufacturers often don’t indicate it on packages. In this case, you should either use the test strips yourself to find out the pH of the remedy or study the recommendations on special resources. For example, Paula Begun in her book "Do not Go to the Cosmetics Counter Without Me" measured the pH of most known acidic products - it can be used as a home guide.
In any case, the only way to establish how often to use acids for a specific person is by trying different concentrations and frequency of use. "Proper exfoliation makes the skin smooth, fresh and soft. Your goal is health-shining skin. The main symptoms that you overdid with acids and it's time to slow down are tightness, flaking, burning, sensation, rashes, cuperose, and pigmentation, - warns the famous British skin care specialist and consultant of several well-known cosmetic brands Caroline Girons. "If you find any of these signs when using acids, then take a break and start using the products for the dehydrated and sensitive skin."
How to choose a product with acids
If the main skin problems are directly related to its surface - small wrinkles, dullness, pigmentation or post-acne, then you should pay attention to the AHA-acids. The FDA recommends using alpha hydroxy acids at a concentration of no more than 10% at home. "Alpha hydroxy acids have proven effectiveness against wrinkles, skin irregularities and pigmentation, which are the result of skin damage from the sun. The best AHA-acids work in a concentration of 5-8%, "says dermatologist Casey Gallagher, one of the authors of the well-known medical research and educational blog VeryWell.
In the case when the main problem that you want to solve with the help of acids is clogged pores and light forms of acne, the main helpers will be the products with BHA-acids that are able to work deep inside the pores. "Salicylic acid reduces the oil content of the skin and has anti-inflammatory properties. By itself, it doesn’t cure acne, but it helps the antibacterial components of cosmetics to penetrate the skin better. BHA-acids work best at a concentration of 1-2% -says Dr. Gallagher.
Some manufacturers offer products containing several acids at the same time, for example, glycolic and salicylic acids. "You can use different acids both together and separately during the day, but with simultaneous use, the risk of irritation and allergic reaction increases. At the same time, some acids in the care for exfoliation are enough, and there is no need to use additional products, such as scrubs or brushes"- experts from the team of Pola Begun advise. Given the risks, the combination of acids is justified when the problem skin suffers from dehydration: in this case, salicylic acid will be disinfected, while glycolic acid will help prevent water loss.
Is it possible to use products with acids in the summer
The use of exfoliating acids in care increases the sensitivity of the skin to the sun and can lead to pigmentation and scarring. This is due to the fact that a layer of keratinized cells on the surface of the skin serves as a natural, weak sunscreen and protects us from UV rays. When using acids, this layer is removed and the skin remains unprotected. Does this mean that it is worthwhile to postpone the use of acids in the summer due to strong solar activity? No. A study by the European Scientific Committee on Cosmetic and Non-Food Products (SCCNFP) showed that when using acids along with a sunscreen with a factor of 15 and above, no additional skin damage from ultraviolet radiation was found compared to people that did not use acids.
It is important to remember that the intensity of UVA radiation is approximately the same regardless of the time of year. Therefore, sunscreen should be used all year round: protection from the sun is one of the most important conditions for preserving the youthfulness of the skin.
- Korean Kiwi Beauty