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Glycolic acid chemical peeling effect and difference from salicylic acid and lactic acid peeling




Chemical peeling is a treatment that improves skin quality by removing old keratin accumulated on the skin using a chemical that exfoliates the keratin .

There are several types of chemical peeling drugs available at medical institutions, one of which is glycolic acid .

Since each drug has its own characteristics, it can be said that the effect of the treatment can be obtained more easily by selecting the drug that suits your skin problems.

In addition, peeling can be done at home, but the chemical peeling drug used at medical institutions has a higher concentration than the drug that can be used at home, so you can expect a higher effect.

On the other hand, the risk of side effects is not zero due to the increased effect.

In addition to the characteristics of glycolic acid compared to other chemical peeling agents, knowing the side effects of glycolic acid in advance allows you to receive a chemical peel that suits you.

Characteristics and action of glycolic acid

Glycolic acid is a type of AHA (a-hydroxy acid)

Glycolic acid is a type of water-soluble AHA. In addition to glycolic acid, there are malic acid, lactic acid, citric acid, and tartrate acid. AHA is also known as fruit acid because it is abundant in fruits, and glycolic acid is contained in sugar cane and grapes.

Glycolic acid is a member of the AHA family, which occurs naturally in foods and has been used for centuries as a cutaneous rejuvenation treatment. Recently it has proved to be a versatile peeling agent and it is now widely used to treat many defects of the epidermis and papillary dermis in a variety of strengths, ranging from 20% to 70%, depending on the condition being treated.

Source : The use of glycolic acid as a peeling agent / National Library of Medicine

Acid name Fruits included
Glycolic acid Sugar cane and grapes
Lactic acid Grapes
Malic acid Apple
Tartaric acid Lemon and grape
citric acid citrus

Glycolic acid and lactic acid are often used in medical institutions as chemical peeling agents in AHA, but since glycolic acid has a smaller molecular size than lactic acid, if used at the same concentration, the reaction by the agent will occur. It is said to be large.

Acid name Molecular weight
Glycolic acid 76.05g / mol
Lactic acid 90.08 / mol
Malic acid 134.08 / mol
Tartaric acid 150.08 / mol
citric acid 192.14 / mol

Glycolic acid has a keratin exfoliating effect that removes old keratin by weakening the junction of "keratinocyte lipids" that connect keratin to each other, leading to improvement of pore clogging .

In addition, when unnecessary keratin is removed, the turnover cycle, which is the metabolism of the skin, is normalized, and improvement of acne, dullness, and age spots can be expected .

Action and effect of chemical peeling

Chemical peeling that adjusts the turnover cycle

The mechanism of turnover and the cause of disordered cycle

The epidermis of the skin consists of layers from the bottom, the basal layer, the stratum granulosum, the stratum granulosum, and the stratum corneum.

Basal cells are present in the basal layer, and the basal cells divide into keratinocytes (keratinocytes). Basal cells are called "stem cells" because they divide continuously to produce keratinocytes. After division, they remain in the basal layer and continue to divide to produce keratinocytes.

Keratinocytes divide and differentiate to form stratum spinosum, stratum granulosum, and stratum corneum, move upward, and eventually peel off. In this way, the process by which basal cells are generated, become keratinocytes, and peel off is called "turnover," and it is said that it takes about 28 days .

Turnover can be disrupted by excessive skin care, UV rays, pollen, stress, etc., which accelerates the cycle, and decreases basal cell division with age, slowing the cycle .

In addition, the accumulation of old keratin also disturbs the turnover cycle .

Normally, human skin has a "barrier function" that protects the skin from external stimuli such as ultraviolet rays and face washing, but when the turnover cycle is disturbed, "NMF" that retains water in the keratinocytes (NMF) (Natural moisturizing factor), the "keratinocyte lipid" that connects the keratins, and the "skin oil film" that prevents the evaporation of water from the skin are out of balance, and the barrier function is weakened. Then, it becomes easy to be affected by external stimuli such as ultraviolet rays and face washing.

Effect of multiple chemical peels

By removing old and hard keratin with chemical peeling and returning the turnover cycle to normal, the barrier function of the skin works normally, and it can be expected to improve dullness, age spots, and dryness.

Improvement of dullness

When the turnover cycle is normalized by chemical peeling and the keratinocytes that form the epidermis are generated in the normal cycle, the NMF that retains the water content of the keratinocytes is also generated in the normal cycle, and the shape and size are uniform. The stratum corneum is formed by the keratinocytes .

The stratum corneum, which is formed of uniform keratinocytes, easily transmits and reflects light inside the skin, making the skin look brighter and improving the dullness of the skin .

Improvement of stains

The melanin pigment that causes age spots is produced in the keratinocytes that are produced in the basal layer of the epidermis. It absorbs ultraviolet rays and turns brown, but it has a function to protect the inside of the skin, and it is originally excreted from the body together with keratin by turnover.

However, if the turnover cycle is disturbed, the melanin pigment will not be excreted and will accumulate in the epidermis, causing spots .

When the turnover cycle is normalized by chemical peeling, the discharge of accumulated melanin pigment is promoted , leading to improvement of spots .

Improvement of dry skin

When the turnover cycle is disturbed and the balance of sebaceous membrane, NMF, and intercellular lipids in the stratum corneum is disturbed, gaps are created between cells. By weakening the barrier function of the skin, it becomes more susceptible to external stimuli such as ultraviolet rays, and the water in the stratum corneum evaporates, drying the skin .

When the turnover cycle is adjusted by chemical peeling, the barrier function of the skin works normally, leading to improvement of dry skin.

Acne prevention

The sebum secreted from the pores mixes with sweat and forms a sebum film that prevents the evaporation of water from the skin. However, when the stratum corneum accumulates on the skin and the stratum corneum thickens, the stratum corneum narrows the exit of the pores and sebum accumulates in the pores.

When the sebum that accumulates in the pores hardens, it becomes a keratin plug, and comedones (comedones), which are the first stage of acne, are formed.

Removing dead skin cells with a chemical peel can prevent comedones by forming a sebum film without the accumulation of sebum in the pores .

Chemical peeling that can be used for other than face

Chemical peels can be used not only on the face but also on the following areas.

  • Decorte
  • back
  • breast
  • On both elbows
  • Below both elbows
  • Waist
  • Butt
  • knee
  • ankle

Reasons why chemical peels cannot be applied to the soles of the feet

A certain amount of acid strength is required to remove the stratum corneum in areas with a thick stratum corneum such as the heel, but it is difficult to adjust and chemical peeling to the sole of the foot is not common.

Since the sole of the foot has a mixture of thick and hard stratum corneum such as the heel and thin and soft stratum corneum such as the arch and between the fingers, if the entire sole is soaked with acid, it will not be the heel. , It may also remove dead skin cells in areas where the skin is thin and soft .

In addition, there are no sebaceous glands on the soles of the feet, the barrier function of the skin is weak, and it is difficult to feel irritation, so it is a site that is prone to alkaline and acidic chemical burns. Therefore, even if it is ineffective, long-term soaking or high drug concentration may cause inflammation .

The National Consumer Affairs Center of Japan is also provided with information on accidents that caused chemical burns due to the use of acid-based foot care products [* 1], so it is necessary to pay sufficient attention to keratin care performed at home.

[* 1] Acid-based foot care products-Chemical burns and severe pain with products that claim keratin care! (National Consumer Affairs Center of Japan homepage)

Precautions before receiving chemical peels

With chemical peels, if the treatment site is damaged, the drug may penetrate deep into the skin and cause inflammation such as sores and redness .

Therefore, please refrain from the following actions when receiving chemical peels.

Days until treatment Notes
3 days ago to the day Face shaving, pack, hair removal, scrub face washing
1 week ago Application of topical acne treatment
3 weeks ago Sunburn
1 month ago Other chemical peels, laser treatment, electric / wax hair removal, permanent makeup

Precautions after receiving chemical peeling

After receiving chemical peeling, your skin will be dry and sensitive and susceptible to irritation, so please refrain from the following actions.

In addition, it is recommended to use sunscreen for about one month after the procedure because it is easy for stains and dryness to occur due to ultraviolet rays.

Days after treatment Notes
Until one week later Facial mask, scrubbing, massage, face sledding, perm color, pool / hot spring, heavy drinking
Until 2 weeks later Excessive sunburn
Until one month later Other chemical peels, laser treatment, electric / wax hair removal, permanent makeup

Those who need to consult a doctor before receiving a chemical peel

  • Pregnant / lactating
  • During herpes treatment
  • Keloid constitution
  • Those who have undergone radiation therapy or surgery within 2 months

Chemical peeling drug used in Japanese cosmetology

There are several types, and the drug and concentration used depends on the depth of the skin you want to penetrate .

In addition, Japanese people have a thinner stratum corneum in the epidermis than Westerners, so they may become inflamed and cause scabs, pigmentation, and sores . Therefore, chemical peeling agents used in Japan tend to be used at a lower concentration than agents used overseas.

Peeling level name Depth to be peeled off Drugs used Indications
1 Shallow layer Horny layer Fruit acid with a concentration of 20% to 35%, salicylic acid Trichloroacetic acid with a concentration of 10% to 20% Acne / Acne Scars Freckles Chloasma
2 Shallow layer Granular layer
3 Middle layer Part of the epidermis-dermis papillary layer Glycolic acid with a concentration of 50% to 70% Trichloroacetic acid with a concentration of 35% to 50% Spot pigmentation
Four Deep Epidermis-dermis papillary layer, reticular layer Baker Gordon liquid Phenol (concentration 88% or more) Deep wrinkles Acne scars Large pores Sagging

Glycolic acid can be adjusted according to the symptoms

The main chemical peeling agents in medical institutions are glycolic acid, salicylic acid macrogol, and lactic acid, but the most frequently used are glycolic acid and salicylic acid macrogol .

Glycolic acid peeling can be a combination of glycolic acid and a pH regulator, and the concentration can be changed according to the symptoms . Therefore, depending on the medical institution, it is possible to formulate drugs according to the symptoms and adapt them to various symptoms.

Glycolic acid can also remove dead skin cells by removing dead skin cells, but macrogol salicylic acid easily binds to sebum in pores and removes dead skin cells while dissolving sebum. It also tends to have fewer side effects than glycolic acid.

In a case-accumulation study using 30% salicylic acid macrogol, which was prepared by a special method for 436 acne patients, an average of 5.9 treatments were performed with no side effects, demonstrating high safety.

Source : Guidelines for the treatment of acne vulgaris / Journal of the Japanese Dermatological Association / Vol. 118 (2008) No. 10

However, it is difficult to formulate salicylic acid and macrogol base, and many medical institutions use predetermined concentrations, so the applicable symptoms are narrower than with glycolic acid.

Glycolic acid with different peeling strength depending on concentration, pH value and application time

Glycolic acid has different peeling strength depending on the concentration, and the concentration can be adjusted according to the skin condition of the person receiving the treatment .

However, Asians, including Japanese, have a thinner epidermis than Westerners, so glycolic acid used in Japanese medical institutions can be exfoliated only in the stratum corneum at a concentration of 10% to 30%. It tends to be many.

Depending on the medical institution, a fixed concentration of glycolic acid may be used, but when performing the treatment with the concentration adjusted, a patching test is performed on the patient's skin in consideration of the condition of acne and the condition of the skin. However, the doctor will judge the appropriate concentration and perform the treatment.

Peeling level name Depth to be peeled off Drugs used Indications
1 Shallow layer Horny layer Fruit acid with a concentration of 20% to 35%, salicylic acid Trichloroacetic acid with a concentration of 10% to 20% Acne / Acne Scars Freckles Chloasma
2 Shallow layer Granular layer
3 Middle layer Part of the epidermis-dermis papillary layer Glycolic acid with a concentration of 50% to 70% Trichloroacetic acid with a concentration of 35% to 50% Spot pigmentation

In addition, the permeation layer of glycolic acid differs depending not only on the concentration but also on the value of "ph", which indicates whether it is acidic or alkaline, and the time of application.

With 7 as the standard, the lower the value of 7, the stronger the acidity and the stronger the peeling effect, and the higher the "ph", the more alkaline the peeling effect . The longer the application time, the deeper the skin penetrates, so the pH value and application time are adjusted to perform the treatment.

In addition, if you apply strongly acidic glycolic acid with a concentration of 30% or more and a pH value of 2 or less to the skin, the skin may become inflamed and scabs or scabs may occur, so care must be taken. ..

Glycolic acid, which has a bactericidal effect, can be expected to be effective against acne.

Glycolic acid not only removes clogged pores, but also has a bactericidal action against P. acnes , which is the cause of acne.

P. acnes is a facultative anaerobic bacterium that dislikes oxygen and grows in the pores by feeding on sebum.

Therefore, chemical peeling with glycolic acid not only removes dead skin cells and prevents sebum from accumulating in the pores, but also aims at skin that is less prone to acne due to the bactericidal effect of P. acnes.

Expected to be effective for wrinkles and crater skin

Glycolic acid chemical peels can also improve crater skin caused by wrinkles and acne.

Crater skin is a condition in which a large amount of collagen etc. is present due to acne inflammation, causing damage to the dermis layer that does not turn over, and the skin becomes uneven.

When glycolic acid is applied to the skin, a protein called "sadokine," which transmits information between cells, is secreted. As a result, fibroblasts that produce collagen and hyaluronic acid are stimulated to promote the production of collagen and the like, and elastin that binds them also increases.

The production of a large amount of collagen, elastin, etc. leads to elastic skin quality, which can be expected to improve wrinkles and craters .

Chemical peeling agents used in addition to glycolic acid

Salicylic acid

Salicylic acid is a type of BHA (beta hydroxy acid) and is a fat-soluble drug.

Chemical peeling with salicylic acid includes ethanol salicylate and macrogol salicylate, but ethanol salicylate is commonly used because it penetrates deep into the skin and can be absorbed by the blood and cause salicyl poisoning. There is macrogol satylate.

Similar to glycolic acid, it can remove dead skin cells and improve pore clogging . In addition, it has the effect of softening the keratin and has an antibacterial effect against ringworm, which is the causative agent of athlete's foot, so it is also used for the treatment of warts, octopuses, and worms.

Difference from glycolic acid

Glycolic acid Salicylic acid macrogol
Type of acid AHA BHA
Acid properties Water soluble Fat-soluble
Feature Desquamation of keratin, weakening of keratin bond Exfoliation, softening of keratin
Side effects Redness, sores, scabs Rarely redness, sores, scabs

Glycolic acid is a water-soluble acid that is easily dissolved in water, while salicylic acid is a fat-soluble acid that is easily dissolved in fat and can remove sebum that has clogged pores, so it can be expected to improve pore clogging.

The combination of salicylic acid and a water-soluble macrogol base reduces transdermal absorbability, which indicates how well the drug dissolves in the skin, preventing the drug from penetrating into layers below the stratum corneum.

Since the drug stays in the stratum corneum, it tends to be less prone to inflammation such as redness and sores caused by deep penetration .

Lactic acid

Lactic acid is a type of AHA that is the same as glycolic acid, and because it has a larger molecule than glycolic acid, it has a shallow penetration into the skin and acts only on the surface layer of the stratum corneum. Since it does not penetrate deep into the skin, the exfoliating effect of keratin tends to be mild .

Therefore, this method is suitable for people who are undergoing chemical peeling for the first time and for sensitive / dry skin.

Trichloroacetic acid (TCA)

Trichloroacetic acid, also called TCA, is a water-soluble acid.

The number of fibroblasts that produce collagen, hyaluronic acid, and elastin, which maintain the firmness and elasticity of the skin, decreases with age. When fibroblasts decrease, collagen, hyaluronic acid, and elastin also decrease, which makes wrinkles and sagging more likely to occur.

By stimulating the dermis layer containing fibroblasts with trichloroacetic acid, a large amount of collagen etc. is produced, which can be expected to improve wrinkles and sagging .

However, trichloroacetic acid may cause pain and pigmentation during the treatment when it is applied to colored races such as Japanese , but it is excessive by using a drug containing low concentration hydrogen peroxide. You can suppress peeling.

Massage peel

Massage peel refers to chemical peeling using a drug called PRX-T33, which is a product of WiQo med of Italy, and its main components are trichloroacetic acid and low-concentration hydrogen peroxide.

While chemical peeling using only trichloroacetic acid damages the epidermis and requires pigmentation and downtime, by adding low-concentration hydrogen peroxide to trichloroacetic acid, the drug extends to the dermis layer while suppressing the peeling action of the epidermis. By infiltrating, it promotes the production of collagen and elastin, and promotes skin regeneration .

Phenolic solution used as a treatment for diseases

Phenol solution is the most exfoliating agent in chemical peels, and the agent penetrates into the reticular layer of the dermis.

The dermis layer is divided into the mammillary body, the subpapillary layer, and the reticular layer from the top, although the boundaries are not clear.

The reticular layer is the thickest layer in the dermis layer, and contains collagen, elastin that binds collagen, and hyaluronic acid. This gives the skin firmness and elasticity.

The penetration of the phenolic solution into the reticulated layer promotes the production of collagen, elastin, and hyaluronic acid.

For Japanese skin with a thin stratum corneum, the use of phenolic solution may increase downtime, such as strong side effects such as redness and sores , and pigmentation caused by the appearance of burn marks. There is .

Therefore, it is rarely used for cosmetic purposes, but it may be used as a treatment for local diseases such as actinic keratosis, superficial basal cell carcinoma, and Bowen's disease.

However, overseas, it is used for deep wrinkles and sagging treatments using anesthetics.

Iontophoresis that can be expected to have a synergistic effect when used in combination with chemical peels

Iontophoresis is a procedure that allows vitamin C and amino acids, which are difficult to inhale through the skin, to penetrate into the skin by passing a weak electric current .

The stratum corneum is acidic and has many positive (+) ions, but from the granule layer below the stratum corneum, there are alkaline and negative (-) ions, and between the stratum corneum and the granule layer. , There is a thin electric film that repels each other and prevents the penetration of beauty liquids.

Therefore, by flowing negative (-) ions with an iontophoresis machine, the electrical film of the stratum corneum and the stratum granulosum weakens, so that beauty essence etc. permeates into the layer below the stratum corneum.

By using chemical peels to remove dead skin cells and then using iontophoresis in combination, the absorption rate of active ingredients such as vitamin C that penetrates into the skin increases .

What you need to know before doing glycolic acid peeling

Glycolic acid peeling fee and number of treatments

Glycolate peeling can be treated at least once every two weeks, and you may feel the effect with one treatment, but by receiving regular treatment, skin turnover It can be expected to improve the skin, which is less likely to cause acne, etc.

Glycolic acid Salicylic acid macrogol
Number of times 3 to 10 times 3 to 6 times
One-time cost 2,500 yen to 20,000 yen 5,500 yen to 25,500 yen

As for the frequency of chemical peeling, it is desirable to perform the treatment once a month according to the cycle of skin turnover.

However, in the case of chemical peeling with glycolic acid, if the skin is not inflamed after the treatment with a low concentration, it may be possible to receive it at least 2 weeks after the previous treatment at the doctor's discretion .

Since chemical peeling is a free medical treatment, not covered by insurance, the cost varies depending on the medical institution and the symptoms and site, but it tends to be cheaper than macrogol salicylate.

In addition, the cost of treatment combined with other treatments such as iontophoresis may be displayed, so please contact each medical institution for details on the cost.

Possible complications of glycolic acid peeling

Glycolic acid can be adjusted in concentration and pH value depending on the symptoms, but if the concentration is increased to allow the drug to penetrate deeply, sores and erythema that causes redness of the skin may occur .

If you experience sores or erythema after the procedure, see a doctor.

If the treatment site is stimulated by ultraviolet rays or chlorine used in swimming pools, it may cause pigmentation or inflammation, resulting in scabs .

Therefore, it is necessary to take measures such as using sunscreen to prevent exposure to ultraviolet rays after the treatment .

Difference between peeling and chemical peeling that can be done at home

Peeling that can be done at home has a low drug concentration

Peeling that can be done at home has a lower concentration than chemical peeling that is done at medical institutions, and is made with safety in mind.

In Japan, glycolic acid, which contains a concentration of 3.6% or more, is designated as a "deleterious substance" under the Poisonous and Deleterious Substances Control Law. [* 3] In order to handle glycolic acid containing 3.6% or more, the person in charge of handling deleterious substances is stipulated by law, such as those who have a pharmacist qualification or those who have completed a department related to applied science. Qualification is required .

In addition, the law stipulates that "deleterious substances" should be strictly managed when used in medical institutions. [※Four]

[* 3] Partial revision of the Ordinance for Designating Poisonous and Deleterious Substances (Notice) (Ministry of Health, Labor and Welfare website)

[* 4] Poisonous and Deleterious Substances Control Law

Types of peeling you can do yourself

Soap peeling

Soap peeling is one of the easy peeling methods at home. It can be used every day and can be used not only on the face but also on the whole body. AHA containing glycolic acid and salicylic acid are used as the main ingredients.

Gel peeling

Gel peels are liquid and rubbed on the skin to form white lumps that entangle old dead skin cells and dirt.

The main components of gel peeling are a gelling agent that hardens when subjected to friction and a cationic surfactant that has sterilizing and bactericidal effects, but there are also gel peeling that contains AHA and salicylic acid.

Chemical peels with high-concentration drugs are available at medical institutions

Chemical peels performed at medical institutions have a higher concentration of chemicals than peels performed at home, so higher effects can be expected.

Glycolic acid peeling can adjust the concentration of the drug according to the condition of the skin and the symptoms, so you can perform the treatment that suits your skin.

Chemical peeling using a high-concentration drug is a medical practice. In the case of a medical institution, even if serious symptoms such as redness and rash occur during peeling, appropriate measures will be taken and the reaction of glycolic acid can be stopped with the alkaline neutralizer "neutralizer". You can .

If you are a medical institution that can handle high-concentration peeling drugs, you can receive effective and safe treatment.

(Updated January 2021)