Who Can Use Chemical Peels?
Professionally administered chemical peels, which is what we will concentrate on in this article, tend to work best on people with a lighter skin tone because the high percentage of acids in professionally administered peels sometimes produce temporary hyperpigmentation (darkening) or even permanent hypopigmentation (lightening) of the skin in darker-skinned people. In rare cases, deeper peels can cause keloid (raised) permanent scarring in people with darker skin as well. These problems tend to increase with the percentage of acid used, so while certain superficial peels may be safe for darker-skinned individuals, it is imperative that people with darker skin speak to an experienced dermatologist before using chemical peels, with particular caution given to medium or deep peels.
While people with darker skin need to proceed carefully when it comes to chemical peels, they can successfully and safely use over-the-counter products that contain the same acids at a lower percentage.
What Are Chemical Peels?
Chemical peels are acids, which are applied to the skin about once every two or three weeks in either an esthetician or doctor’s office.1-2Doctors can administer peels in up to 70% strength, and estheticians in spas and salons can administer peels in up to 30% strength.
- Glycolic acid
- Salicylic acid
- Lactic acid
- Polyhydroxy acid
- Amino fruit acid
- Pyruvic acid
- Trichloracetic acid (TCA)
- Jessner's peel
The acid is left on the skin for a few minutes (3-5 is typical) and then removed. Depending on the strength and type of peel, the acids in a chemical peel cause the skin to peel and sometimes blister over a period of a few days. This exfoliation signals the cells inside the skin to regenerate faster, which can help hasten skin turnover, improve skin texture, and prevent pores from becoming clogged.1,3
At this time there is no evidence showing whether any one type of acid works better than another. From the data we currently have, they all appear to have similar efficacy.1,3-7
Chemical peels are classified based on the type of acid and concentration. The main types of professionally administered chemical peels include (1) superficial, (2) medium, and (3) deep peels. Superficial peels are usually used for the treatment of acne, medium peels are used for the treatment of both acne and acne scars, and deep peels are usually only used to treat acne scars.
Chemical peels, especially superficial peels, can be used alongside other medications. This is often the desired course of action since chemical peels produce incomplete clearing of the skin on their own. If you decide to try a chemical peel, be sure to ask your practitioner before adding in other medications.
Over-the-counter acids: There are lower-strength acids available over-the-counter that can be applied at home on a more regular basis, producing a slower and more manageable exfoliation of the top layers of the skin without the side effects and cost of professionally administered chemical peels. An example of this is 10% glycolic acid. Most people can handle this type of over-the-counter product every 2-3 nights. For the purposes of this article, however, we’ll stick to talking about higher percentage, professionally administered peels.
Superficial Peels – Treats Acne
Superficial peels penetrate only the surface layer of skin, helping to shed cells on the skin’s surface. They also have anti-inflammatory properties and can help temporarily reduce skin oil secretions. They are lower strength than medium or deep peels and normally use acids that belong to the alpha hydroxy acid (AHA) or beta hydroxy acid (BHA) families. The most common types of acids used are glycolic acid (AHA) and salicylic acid (BHA).1Both glycolic and salicylic acid peels are typically administered at a concentration of 30% and can be applied either at the doctor’s office or at an esthetician’s salon.
Effectiveness. Most people report a "fair" to "good" result. Results tend to last for 1-2 months, with acne beginning to reassert itself at this time.
According to a 2011 article in the Journal of the European Academy of Dermatology and Venereology, “when used in mild-to-moderate facial acne, superficial peels reduce acne lesions with an effect that becomes more apparent with increasing numbers of treatments. Improvements in both inflammatory and non-inflammatory lesions have been reported, but the effect on nodulocystic acne is minimal.”1
Studies have reported that salicylic acid peels reduce acne by 47 to 75%.1,6,8-10Glycolic acid peels also appear to be effective, with 50 to 95% of patients experiencing a significant improvement in acne after at least 3 glycolic acid treatments.1,11-14Since studies on glycolic acid did not report what the percentage improvement, it is difficult to conclude exactly how effective glycolic peels are when compared with salicylic acid, but from what we can garner from medium and deep peels, the type of acid is secondary to the concentration.
Side effects. Superficial chemical peels are generally well tolerated and side effects depend on the type of chemical peel used. Most people experience a sunburnt look with obvious peeling of the skin in the days after their first peel. This redness and peeling tends to be less pronounced with each consecutive peel. The most common side effects are dry skin, reddening, and burning sensations.1The most severe side effects tend to be experienced after the first treatment, and subside with subsequent treatments.6Because chemical peels remove the protective layers of the skin, your skin will be much more sensitive to sunlight.2It is extremely important to keep your skin out of the sun after a peel and to use an adequate sunscreen until the peeling process is complete.
Moderate Peels – Treats Acne and Light Scarring
Moderately penetrating chemical peels normally use trichloroacetic acid (TCA) in 35-50% strength, which penetrates more deeply into the skin than superficial peels. TCA causes peeling of deeper layers of the skin and increases production of collagen, elastin, and other proteins which give skin its elasticity.15However, since 50% strength TCA can cause complications, including scarring at times, doctors now often prep the skin using other methods, and then apply only 20-35% TCA. This produces similar results with fewer complications. The methods of prepping the skin before 20-35% TCA include: (1) freezing the skin with CO2 and acetone, (2) applying Jessner’s solution, a type of peel that consists of a combination of lactic acid (which helps exfoliate skin), salicylic acid (which helps skin penetration), and resorcinol (which helps break down hardened skin and treats acne), and (3) applying 70% glycolic acid.16
Effectiveness. Moderate peels are not normally used to treat acne. Therefore, we do not have any studies reporting on the effectiveness of medium depth peels on acne. One clinical study did investigate the effect of TCA on acne, but in superficial peel percentages. The authors of that study reported that TCA treatment resulted in some improvement in acne in 85% of patients. Superficial-percentage TCA was particularly effective in treating papules and pustules (inflamed “zits”), and less effective in treating comedones (small, non-inflamed whiteheads and blackheads). Compared to salicylic acid peels, TCA was more effective in treating comedones, but less effective in treating inflammatory lesions. The authors stated, “This study, comparing the effect of 25% TCA and 30% salicylic acid peel in the treatment of acne vulgaris, demonstrates that both peels are successful for the treatment of moderate and mild acne in [darker] skin type patients without complications. The authors show that the 25% TCA peel is superior in treating comedonal lesions, whereas the 30% salicylic acid peel is superior in treating inflammatory lesions.”17
Another study evaluated the efficacy of Jessner’s solution with 20% TCA for treatment of acne scars. All 50 patients included in the study showed some improvement in their acne scars, with 60% of patients reporting “marked improvement,” which was defined as a reduction of acne scars of over 70%. “In Group I (Jessner's peel and 20% TCA), mild improvement of acne scars was seen in 8% cases, moderate improvement in 32% cases and marked improvement of acne scars was seen in 60% patients. In Group II (20% TCA alone), mild improvement of acne scars was seen in 32% cases, moderate improvement in 40% cases and marked improvement of acne scars was seen in 28% patients.”18
Side effects. Because moderate peels penetrate deeper layers of the skin, they produce more severe side effects than superficial peels. These side effects include reddening of the skin, swelling, and darkening of the skin.18In most cases, these side effects subside within one week of treatment. TCA peels are not indicated for use in patients with darker skin, as they may result in permanent darkening of the skin in the area where the peel was used. However, this problem can be overcome if TCA is used in combination with Jessner’s solution. “To conclude, Jessner's solution can be an adjuvant treatment with TCA in the treatment of acne scars, improving the results and minimising post inflammatory hyperpigmentation. Using modified Jessner's solution combined with 20% TCA, the risk of post inflammatory hyperpigmentation, which occurs in dark skinned persons after TCA peels, can be reduced.”18As with any type of peel, it is important that you carefully avoid any sun exposure whatsoever in the days following the peel.
Deep Peels – Treats Scarring
Deep peels penetrate most deeply into the skin and are used to treat acne scars. Because deep peels use very strong acids, the procedure is akin to plastic surgery and must be administered by a skilled and highly trained dermatologist. Deep peels use phenol at a concentration of 88%. In some cases, phenol is combined with croton oil. Deep peels work by breaking down proteins in skin and stimulating production of collagen in the regenerated skin.19
Effectiveness. A clinical study on 10 patients with acne scars reported that a phenol peel reduced acne scars by 75%.20“Acne scarring improved in 100% of patients. The overall scar severity score improved by a mean of 75.12%.”20
Another study, conducted in 11 patients showed that phenol peels reduced acne scars. “The acne scars group had an improvement of over 51% in 64% of the cases.”21
Side effects. Deep chemical peels completely remove the top layer of the skin. Side effects of deep chemical peels are severe and include bleeding, swelling, crusting, and prolonged reddening of the skin and skin discoloration.19These side effects can be long lasting and can take up to 6 months to go away.21Unlike superficial and medium peels, phenol peels are absorbed through the skin into the bloodstream and can cause breathing problems, kidney problems, and serious heart complications.19,21Deep peels are not indicated for darker-skinned individuals because of the chance of permanent skin lightening and the potential for keloid scarring. Similar to the lighter types of peels, it is absolutely vital to avoid any sun exposure whatsoever after a deep chemical peel for the amount of time determined by the doctor.