Paul M. Graham, DO
Edited by Lacey Elwyn, DO
Chemical peels are one of the oldest cosmetic procedures performed, with historical records dating back to ancient Egypt. During this era, various oils and acids were applied to the skin in an attempt to achieve skin rejuvenation. In the late 19th century, chemical peels became popular for therapeutic purposes. Greek and Roman physicians used grape juice, lemon extracts, and sour milk in an effort to induce superficial peeling. In the early 1940s, physicians became more aware of the science behind chemical peels, allowing for more tailored treatment for specific indications including anti-aging, acne, pigmentation, and scarring.
A chemical peel is a specialized procedure that produces controlled partial-thickness wounding of the skin to induce shedding of varying layers and wound healing by secondary intention. This procedure can be used on the face, hands, neck, and chest to reduce the appearance of fine lines/wrinkles and textural irregularities, brighten one’s complexion, exfoliate the overlying skin, treat acne and resultant scarring, and mitigate existing sun damage. The benefit of chemical peels extends far beyond our current understanding. Ongoing research strives to elucidate a chemical peel agent that will offer the most effective results with minimal to no downtime and high patient satisfaction.
Before explaining how chemical peels actually work, a basic understanding of skin anatomy is needed. The skin is a multilayer structure composed of the epidermis, dermis, and subcutaneous layer.
The epidermis makes up the top layer of the skin and is composed of 4-5 different layers of cells called keratinocytes. The outermost layer of the epidermis, the stratum corneum, forms our skin barrier and protects us from the external environment. The next layer of skin, the dermis, lies directly beneath the epidermis. This layer is composed of collagen, a structural protein responsible for support and integrity of the skin. Collagen serves as a major structural protein not only in skin, but also in tendons, ligaments, and bone. Below the dermis, lies the subcutaneous tissue. This layer is composed of fat lobules responsible for a variety of important functions including buoyancy, energy storage, and hormone production.
How Chemical Peels Work
As discussed above, chemical peels work by inducing controlled partial-thickness wounding of the skin, removing the upper layers of the epidermis and dermis in superficial peels and can remove the deep dermis in medium to deep chemical peels, both allowing for new tissue production. As the skin begins to heal, new collagen is produced, leading to improvement in texture, tone, pigment, acne scarring, and fine lines/wrinkles.
During the procedure, a chemical solution is applied to the surface of the skin for a temporary amount of time, allowing for adequate absorption to take place. There are various factors that play a role in the depth of the peel. These factors include peeling agent concentration, amount of time left on the skin, treatment location, application technique, peel frequency, and skin quality.
One interesting fact related to chemical peels is that the higher the density of sebaceous (oil) glands in the treatment area, the less susceptible this area will be to the peeling agent. Simply put, the more oily the skin, the less of an effect the peeling agents will have on the treatment location. This explains why it is very important to adequately remove all the surface oils prior to the application of the peeling agent. This can be done effectively with topical acetone or a similar degreaser.
Chemical peels are often classified by the depth of penetration and divided into superficial, medium, and deep peels.
- Superficial peels, also known as “lunchtime peels”, have very limited skin penetration, targeting only the outermost layer of the epidermis called the stratum corneum. Due to this limited penetration, the adverse effects are limited with minimal to no downtime. Another highlight of superficial peels is its ability to be used in darker skin types with low risk of pigmentary changes as opposed to its deeper peeling counterparts. These peels are extremely popular given the low cost, rapid healing, and minimal risk associated. Due to the limited penetration of these peels, consecutive treatments are recommended 2-4 weeks apart, offering cumulative results. Indications for superficial peels include acne, melasma, and discoloration. Superficial peeling agents include trichloroacetic acid (TCA) 10-25%, salicylic acid, tretinoin solution, Jessner’s solution (resorcinol/salicylic acid/lactic acid) and alpha hydroxy acids (AHAs) such as glycolic acid, lactic acid, and mandelic acid.
- Medium depth peels have a higher depth of penetration into the epidermis with limited extension into the dermis. The peel induces coagulation necrosis (cell death) extending down to the upper dermis. This depth of penetration allows for collagen regeneration and remodeling to take place. Medium depth peels are often indicated for skin lesions that grow on the top layer of the skin such as actinic keratosis, seborrheic keratosis, pigmented lesions, superficial scars, and fine line/wrinkles. These peels often cause redness and swelling immediately following the procedure. Swelling is usually the first to subside followed by redness over 48-96 hours. The new layer of skin will typically develop over 3-7 days after treatment. Similar to superficial peels, consecutive treatments are recommended every 4-6 weeks until noticeable clinical improvement. Medium depth peeling agents include glycolic acid, trichloroacetic acid (TCA), and pyruvic acid.
- Deep peels, although not often used much anymore, still have utility in the treatment of fine lines/wrinkles and textural abnormalities. A chemical called phenol was first used in the early 1950s for anti-aging purposes, demonstrating dramatic results in the improvement of skin texture and appearance. Deep peels, if done correctly, cause coagulation necrosis (cell death) down to the level of the deep dermis, inducing extensive collagen rejuvenation and remodeling through the wound healing process. The new skin typically appears after 1-2 weeks following the procedure. Deep peels are often performed in the hospital setting with IV sedation and cardiac monitoring due to associated discomfort and risk of cardiotoxicity. As a result of the prolonged downtime with this type of chemical peel, few people elect to undergo this procedure. Despite the delayed recovery, the results are often dramatic and long-lasting. Deep peeling agents include phenol and trichloroacetic acid.
Am I a candidate for chemical peels?
The ideal patient for chemical peels is one with fair skin and light hair; however, various superficial peels can be performed on those with darker skin types with good results. Realistic expectations and a thorough understanding of the procedure is required prior to this procedure. Many different types of chemical peeling agents exist and your doctor will choose which one is best for your specific needs and skin type. Smoking is also a relative contraindication to the procedure. Smoking has been shown to slow the wound healing process and may prolong and complicate a normal recovery.
What are the risks associated with chemical peels?
Serious adverse effects rarely occur with chemical peels, but certain risks do exist. Although infrequent, scarring, infection, swelling, hypopigmentation, hyperpigmentation, and the development of cold sores may occur. It is important to follow specific post-treatment instructions to minimize risk and facilitate good results.
What should I expect during the procedure?
Prior to a chemical peel, the provider will cleanse the skin with an antiseptic and remove any left-over surface oils with acetone. The chemical solution will then be applied to the treatment area with either a brush or a gauze pad and left in place for approximately 2-10 minutes depending on the peeling agent being used. During the procedure, a slight to moderate burning pain may be experienced. The more superficial the peel, the less associated discomfort. After the desired application time, depending on the chemical peel used, such as glycolic acid, a neutralizer solution will be applied to the face to “neutralize” the acid and stop any further penetration from occurring. Generally speaking, chemical peels that leave a frost; TCA, Jessner’s solution, and salicylic acid, do not require neutralization. The provider will often apply a moisturizer cream or ointment to the treatment location in addition to a layer of sunscreen.
What should I expect after a chemical peel?
Depending on the depth of the peel, redness and swelling are common and often resolve within 12-72 hours following the procedure. Deep peels, on the other hand, cause significant redness and swelling, often taking several weeks for resolution. After most chemical peels, the skin will be red, tight, and swollen. Immediately following the peel, it is recommended to apply petrolatum ointment to help keep the skin moisturized. NSAIDs, ice packs, or a fan may be used to help relieve discomfort. It is imperative to avoid sun exposure following any chemical peels. The reason behind this recommendation is that our skin barrier is compromised, decreasing our bodies ability to protect our skin from the sun’s ultraviolet radiation, potentially leading to the development of skin cancer down the road. It typically takes 48 hours before any peeling occurs and may last from 2-10 days depending on the peeling agent used. Your regular skin-care regimen may be resumed once the skin appears to be well healed with minimal redness, peeling, and swelling; usually within 2-5 days. Tretinoin, a topical vitamin A medication, may be resumed 7-14 days following the peel and should be stopped at least 5-7 days before any subsequent chemical peel treatments.
How can I prolong the results?
Chemical peels often provide only temporary improvement if a routine anti-aging skin care regimen is not undertaken. Topical regimens are vital in prolonging the results obtained from chemical peels. It is highly recommended to speak with your dermatologist about starting an effective anti-aging regimen incorporating a broad spectrum sunscreen, topical retinoids (vitamin A), topical antioxidants, and a good moisturizer.
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Photo Credit: Theperfectdermapeel.com, Headandneckcancerguide.org, Family West Dentistry, Naturalskinshop.com
Cox SE, Soderberg J, Butterwick KJ. Chemical Peels. In: Robinson JK, Hanke CW, Siegel DM, et al. Surgery of the Skin: Procedural Dermatology. Elsevier; 2010:394-412.
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