Medical Encyclopaedia › Chemical peel (short definition)
In brief: In a chemical peel, an acid solution is applied to the skin which detaches upper layers of the skin in a controlled way. The skin then renews itself from deeper layers. Depending on the acid, concentration and contact time, the effect ranges from gentle smoothing of the surface to deep skin renewal with a longer healing time. The deeper the peel, the stronger the possible effect – but also the risk.
How does a chemical peel work?
The acid loosens the cohesion of the horny cells or deliberately damages cells of the epidermis and dermis. This is followed by wound healing: new epidermis grows back and, with medium and deep peels, new collagen can be formed in the dermis. Three depths are distinguished:
- Superficial peels: for example with glycolic acid and other fruit acids, salicylic acid or mandelic acid; they act in the epidermis and are usually applied as a series.
- Medium peels: often with trichloroacetic acid in medium concentration, sometimes combined with a preparatory peel; they reach into the upper dermis.
- Deep peels: with phenol solutions; they act down to the mid-dermis and are now only rarely used, under medical supervision.
What is it used for?
Superficial peels may be considered for mild to moderate acne, enlarged pores, dull skin and as an adjunct for pigmentation disorders such as melasma or dark spots after inflammation. Medium peels are used for sun-related skin ageing with fine lines, shallow acne scars and, in selected cases, actinic keratoses. Deep peels are intended for pronounced wrinkles, for example around the mouth. Deep, depressed scars or lax skin usually cannot be improved sufficiently with peels alone.
Procedure
Before treatment, skin type, pre-existing conditions, medicines and previous treatments are clarified. The skin is often prepared for a few weeks with skincare products and consistent sun protection. If there is a known tendency to cold sores, an antiviral is often given as a precaution before medium and deep peels. The skin is cleansed and degreased, then the solution is applied for a set time and neutralised or washed off depending on the acid. A burning sensation during the contact time is usual. Deep phenol peels require cardiovascular monitoring, because phenol can be absorbed through the skin and trigger heart rhythm disorders.
Healing and aftercare
After superficial peels, the skin is usually only briefly red and flakes slightly for a few days. After medium peels, the skin turns dark, peels off over about a week and remains red for a few weeks afterwards. Deep peels require several weeks of healing, and the redness can last months. In every case: do not pick off crusts, use mild care and consistently protect the skin from the sun for weeks to months. The US Food and Drug Administration (FDA) points out that products containing fruit acids can increase the skin’s sensitivity to the sun.
Risks and limits
- dark pigment spots after the inflammation, especially with darker skin
- light, less pigmented areas, especially after deep peels, sometimes permanent
- persistent redness, irritation, contact allergies
- flare-up of cold sores, bacterial or fungal infections
- scars, especially with too deep application, infection or previous treatment with isotretinoin
- with phenol peels, additionally heart rhythm disorders
Treatment should not be carried out with open wounds, active infections or eczema in the treatment area, a strong tendency to scarring, and during pregnancy and breastfeeding, depending on the acid. After isotretinoin therapy, a time interval is usually advised before medium and deep peels.
Costs and important to know
Peels for aesthetic purposes are paid for privately. Over-the-counter skincare products contain much lower acid concentrations than medical peels and have a correspondingly weaker effect. Medium and deep peels belong in experienced medical hands, ideally in a dermatology practice. Detailed information about downtime, risks and realistic results and time to reflect are advisable. Depending on the findings, alternatives are microneedling, laser treatments, consistent retinoid therapy or, for acne, initially guideline-based drug treatment.
Related terms in the encyclopaedia
Glycolic acid, Salicylic acid, Melasma, Post-inflammatory hyperpigmentation, Acne scar treatment, Skin ageing, Microneedling, Laser resurfacing, Herpes
Sources
- U.S. Food and Drug Administration (FDA): Alpha Hydroxy Acids – Information for Consumers
- American Academy of Dermatology (AAD): Chemical peels – Overview and FAQs
- Soleymani T, Lanoue J, Rahman Z: A Practical Approach to Chemical Peels: A Review of Fundamentals and Step-by-step Algorithmic Protocol for Treatment. J Clin Aesthet Dermatol 2018
- Deutsche Dermatologische Gesellschaft (DDG): Patienteninformationen zu ästhetisch-dermatologischen Verfahren
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor, dentist or pharmacist. Last updated: October 2026.