* Chemical peels are somewhat effective for ice pick scars but work best for boxcar and rolling scars.
A chemical peel is a mixture of chemicals applied to the skin to strip away the top layers of the skin. The goal is to cause a controlled injury and trigger the body’s natural healing process. As the skin rebuilds, it will produce more collagen and elastin (proteins naturally found in the deeper layers of the skin), which should improve the appearance of acne scars once healing is completed.1
Chemical peels differ in how deep they penetrate into the skin. Stronger peels penetrate deeper into the skin and can provide better results, but also carry a higher risk of side effects.1 Chemical peels fall into three types based on how deep they penetrate into the skin.
Medium-depth peels remove the entire epidermis as well as a deeper layer called the papillary dermis, and thus can treat deeper scars.
When it comes to treating acne scars, light peels are not very effective. In general, medium-depth or deep peels are necessary to see significant improvement in the appearance of scars.2
With light and medium-depth peels, multiple (3-6) treatments spaced out at intervals of 2-3 weeks are often necessary to achieve the desired effect.4-7 With deep peels, a single treatment is sufficient.8,9
CAUTION: People with dark skin need to approach medium-depth and deep chemical peels with caution because these peels carry a significant risk of skin pigmentation changes, such as prolonged skin darkening (hyperpigmentation).10
As with all scar revision treatments, chemical peels are sometimes combined with other scar revision procedures to achieve desired results.
People with active acne should not undergo acne scar repair of any kind, including chemical peels. Make sure your skin is clear of acne before beginning scar treatment.
Before agreeing to undergo treatment with a chemical peel, ask multiple doctors about their opinions, proposed treatments, expected outcomes, and prices.
The chemicals used in chemical peels are usually different types of acids, which corrode (eat away at) the skin when they are applied to the skin surface. For light peels, doctors use weak acids or low concentrations of strong acids. For deeper peels, stronger acids and/or higher concentrations of acids are used.
Medium-depth peels contain one of the following chemicals:1,3,10
- TCA (trichloroacetic acid) in medium concentrations from 20% to 40%*.
- A combination of TCA (trichloroacetic acid) and one of the following light / superficial peel ingredients:
- An alpha-hydroxy acid (AHA)
- A beta-hydroxy acid (BHA)
- Jessner’s solution
* TCA (trichloroacetic acid) is the “gold standard” of chemical peel treatments–in other words, it is the most common and most frequently recommended chemical peel for acne scars. This is because, if applied correctly, a TCA peel provides the best balance of high efficacy and relatively low side effects. TCA can act as a light, medium-depth, or deep peel depending on the concentration: the higher the concentration, the deeper the peel. After the application of a TCA peel, a characteristic white “frost” appears on the skin.10 Today, TCA is often applied using a new technique called CROSS (Chemical Reconstruction Of Skin Scars).
Medium-depth peels: Anesthesia for medium-depth peels is optional, as pain during the procedure is typically mild and tolerable. Most doctors offer the option of anesthesia or sedation, which can be one of the following types:
- A combination of an oral sedative with an oral pain reliever.
- An injection of a sedative into a vein (intravenously).
- An injection of an anesthetic into a facial muscle (intramuscularly).
- General anesthesia3,6.
Acne scars before (left) and after six sessions (right) of a medium-depth chemical peel.
- Levy LL, and Zeichner JA. Management of acne scarring, part II. A comparative review of non-laser-based, minimally invasive approaches. Am J Clin Dermatol. 13(5), 331-340 (2012).
- Uptodate.com. Management of acne scars. Available from: https://eresources.library.mssm.edu:3285/contents/management-of-acne-scars?source=search_result&search=management%20of%20acne%20scars&selectedTitle=1~27#H1673698. Last retrieved on 6 September, 2017.
- Landau M. Chemical peels. Clin Dermatol. 26(2), 200-8 (2008).
- Garg VK, Sinha S, and Sarkar R. Glycolic acid peels versus salicylic-mandelic acid peels in active acne vulgaris and post-acne scarring and hyperpigmentation: a comparative study. Dermatol Surg. 35(1), 59-65 (2009).
- Puri N. Efficacy of Modified Jessner’s Peel and 20% TCA Versus 20% TCA Peel Alone for the Treatment of Acne Scars. J Cutan Aesthet Surg. 8(1), 42-5 (2015).
- Al-Waiz MM, and Al-Sharqi A. Medium-depth chemical peels in the treatment of acne scars in dark-skinned individuals. Dermatol Surg. 28(5), 383-7 (2002).
- Sachdeva S. Lactic acid peeling in superficial acne scarring in Indian skin. J Cosmet Dermatol. 9(3), 246-8 (2010).
- Leheta TM, Abdel Hay RM, and El Garem YF. Deep peeling using phenol versus percutaneous collagen induction combined with trichloroacetic acid 20% in atrophic post-acne scars; a randomized controlled trial. J Dermatolog Treat. 25(2), 130-6 (2014).
- Park JH, Choi YD, Kim SW, Kim YC, and Park SW. Effectiveness of modified phenol peel (Exoderm) on facial wrinkles, acne scars and other skin problems of Asian patients. J Dermatol. 34(1), 17-24 (2007)
- Kontochristopoulos G, and Platsidaki E. Chemical peels in active acne and acne scars. Clin Dermatol. 35(2), 179-182 (2017).
- Brody HJ. Complications of chemical peeling. J Dermatol Surg Oncol. 15(9), 1010-1019 (1989).
- Erbağci Z, and Akçali C. Biweekly serial glycolic acid peels vs. long-term daily use of topical low-strength glycolic acid in the treatment of atrophic acne scars. Int J Dermatol. 39(10), 789-94 (2000).
- Mackee GM, and Karp FL. The treatment of post-acne scars with phenol. Br J Dermatol. 64(12), 456-9 (1952).