What is a chemical peel: chemoexfoliation for skin rejuvenation
A chemical peel — or chemoexfoliation — is a procedure in which a chemical agent of defined concentration is applied to the skin, causing controlled destruction of skin layers, followed by regeneration and remodeling. This technique has been used for centuries to improve signs of photoaging, and its scientific evolution has progressed considerably over recent decades.
The caustic agents used cause controlled keratocoagulation and protein denaturation in the epidermis and dermis, releasing pro-inflammatory cytokines and chemokines. This targeted inflammation activates the normal healing signaling cascade, including stimulation, development and deposition of new dermal collagen and elastin, reorganization of structural proteins and connective tissue, as well as regeneration of new keratinocytes.
The result: rejuvenation and thickening of the epidermis, increased dermal volume, and improvement of superficial and medium dyspigmentation.
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Mechanism of action of chemical peels
When a peeling agent is applied to the skin, it penetrates to a specific depth depending on its concentration, application time, formulation, and the type of skin being treated. This penetration creates a controlled skin injury that activates the natural healing process.
Keratocoagulation and protein denaturation: The acids used denature skin proteins, leading to tissue coagulation. For trichloroacetic acid (TCA), this coagulation produces a visible "frost" or whitening of the skin, indicating the depth of penetration.
Release of inflammatory cytokines: The chemical injury triggers the release of inflammatory mediators that attract repair cells to the treated area.
Stimulation of neocollagenesis: Fibroblasts are activated and produce new type I and III collagen, as well as elastin. This production increases dermal density and thickness, improving skin firmness.
Exfoliation and epidermal regeneration: Damaged skin layers progressively desquamate, revealing fresh and regenerated epidermis. Accelerated cell turnover improves texture, radiance and evens out skin tone.
Continuous remodeling: The mechanical action of peeling, even when limited to the epidermis, stimulates regeneration via dermal pathways. Remodeling continues for several weeks to months after treatment.
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Classification of peels by depth
Chemical peels are classified according to the depth of skin penetration, a determining factor for results, recovery time and potential risks.
Very superficial peels: Affect only the stratum corneum. Examples: 20-50% glycolic acid for 1-4 minutes, 10-30% salicylic acid for 4-6 minutes. Minimal recovery time, subtle results, safe for all skin types.
Superficial peels: Cause necrosis down to the basal layer of the epidermis. Examples: 20-70% glycolic acid for 2-10 minutes, 10-30% salicylic acid for 5-6 minutes, 10-30% TCA (1 layer). Recovery time: a few days, effective for epidermal pigmentation and fine texture.
Medium peels: Reach the complete epidermis and papillary dermis. Examples: 35% TCA, Jessner's solution + 35% TCA, 70% glycolic acid + 35% TCA. Recovery time: 7-10 days, treat moderate wrinkles, acne scars, significant photoaging.
Deep peels: Penetrate to the mid-reticular dermis. Example: phenol (Baker-Gordon formula). Recovery time: 2-3 weeks, spectacular results but significant risks. Not recommended for dark skin.
Fundamental principle: peel depth is directly proportional to improvement in results and the number of potential complications. Multiple superficial peels are not equivalent to a single deep peel.
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Ideal candidates for a chemical peel
Chemical peels are suitable for a wide population thanks to the variety of agents and depths available. Appropriate patient and peel type selection is crucial for safety and efficacy.
You are probably a good candidate if:
- You wish to treat photoaging, hyperpigmentation, active acne, acne scars, or irregular texture
- You have realistic expectations regarding possible results according to the chosen peel depth
- You can avoid sun exposure and follow a strict sun protection protocol
- You have no medical contraindications
- For dark skin (Fitzpatrick IV-VI), you accept the necessary additional precautions
You are probably not a candidate if:
- You are pregnant or breastfeeding
- You are taking isotretinoin (Roaccutane) or have taken it in the last 6-12 months
- You have an active skin infection, active herpes, or open wounds
- You are predisposed to keloids or hypertrophic scars
- You cannot avoid sun exposure or follow post-treatment care
- You have undergone recent facial radiotherapy
- You have unrealistic expectations or body dysmorphia
Treatment areas with chemical peels
Chemical peels can treat various areas of the body, although the face remains the most frequently treated area.
Face:
- Global photoaging (fine lines, rough texture, enlarged pores)
- Hyperpigmentation and dyschromia (melasma, sun spots, post-inflammatory hyperpigmentation)
- Mild to moderate active acne
- Atrophic acne scars
- Periorbital and perioral fine lines
- Irregular texture and dull skin
Neck and décolletage: Photoaging, hyperpigmentation, rough texture. Peels must be more superficial as the skin is thinner there.
Back of hands: Age spots, rough texture, photoaging.
Areas to treat with caution:
- Periorbital region: skin is very thin, increased risk of complications
- Neck and décolletage: lower concentrations necessary
- Non-facial areas: slower healing, increased risk of hyperpigmentation
Dangerous areas: Medial canthi and periapical triangles/nasojugal folds require special protection to avoid complications.
Types of chemical peeling agents
Peeling agents are classified according to their chemical structure and properties.
Alpha-hydroxy acids (AHA):
- Glycolic acid (20-70%): Most widely used, small molecular size allows deep penetration, effective for photoaging and pigmentation
- Lactic acid (30-90%): Gentler than glycolic, good for sensitive skin
- Mandelic acid (10-40%): Large molecular size, slow penetration, excellent for dark skin and acne
Beta-hydroxy acids (BHA):
- Salicylic acid (20-30%): Lipophilic, penetrates pores, excellent for acne and oily skin. Forms a "pseudofrost" when the acid crystallizes. Particularly effective for dark skin due to minimal risk of PIH.
Trichloroacetic acid (TCA) (10-50%):
- 10-30% concentration: superficial peel
- 35% concentration: upper limit of medium peel
- Functions as a keratocoagulant producing white frost
- Does not require neutralization
- More discomfort and desquamation than AHAs
Jessner's solution:
- Combination: lactic acid + salicylic acid + resorcinol
- Classic peel, effective for acne and pigmentation
- Often used in combination with TCA for more uniform penetration
Modern combination peels:
- Salicylic-mandelic solution
- Combined brightening peels
- Formulas containing pyruvic, ferulic, azelaic acid, or retinol
Process of a chemical peel session
Preparation (2-4 weeks before): Essential to optimize results and minimize complications. Skin "priming" with strict sunscreen, hydroquinone (for melasma/hyperpigmentation), tretinoin. For dark skin, this preparation is absolutely crucial.
Day of treatment:
- Complete cleansing and degreasing of the skin (remove oils, makeup, residue)
- Protection of sensitive areas (eyes, nostrils, labial commissures)
- Systematic application of peeling agent according to a defined pattern (generally from forehead downward)
- Monitoring endpoints:
- Glycolic acid: predetermined duration (generally 3 minutes) or appearance of erythema/epidermolysis
- TCA: white frost (degree of whiteness indicates depth)
- Salicylic acid: pseudofrost (crystallization)
- Neutralization (if necessary): 10-15% sodium bicarbonate for glycolic, cold water for TCA
- Application of soothing and protective care
Duration: 15-45 minutes depending on agent, area and depth.
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Sensations: Tingling, mild to moderate burning depending on concentration. TCA generally causes more discomfort than AHAs. Cooling with fan or cold compresses improves comfort.
How many chemical peel sessions are necessary
The number of sessions depends on the indication, peel depth and severity of the problem being treated.
Superficial peels:
- Mild photoaging: 4-6 sessions spaced 2-4 weeks apart
- Active acne: 4-6 sessions spaced 2-3 weeks apart
- Post-inflammatory hyperpigmentation: 5-6 sessions spaced 2-3 weeks apart
- Maintenance: periodic sessions every 1-3 months
Medium peels:
- Moderate photoaging: 1-3 sessions spaced 3-6 months apart
- Acne scars: 2-4 sessions spaced 3-4 months apart
- Melasma: 3-6 sessions spaced 4-6 weeks apart (with pigment preparation)
Deep peels:
- Severe photoaging, deep wrinkles: generally 1 single session
- Long-lasting results (10-20 years documented), but invasive procedure
Cumulative principle: exfoliation depth is cumulative dose-dependent. Multiple applications or "passes" of a superficial agent are not equivalent to a single application of a medium agent.
Chemical peel results: realistic timeline
Superficial peels:
- Immediately after: Erythema, slight heat sensation
- Days 1-3: Persistent redness, tight skin, beginning of slight fine desquamation
- Days 4-7: Complete desquamation, fresh skin revealed, diminishing erythema
- Weeks 2-4: Improved radiance, smoothed texture, more even skin tone
Medium peels:
- Immediately after: Marked erythema, white frost (for TCA), burning sensation
- Days 1-3: Moderate edema, bronzed/dark skin, significant sensitivity
- Days 4-7: Significant desquamation in large patches, persistent erythema
- Days 8-14: Complete re-epithelialization, pink and fragile skin, makeup possible
- Weeks 3-8: Residual erythema gradually diminishing, visible improvement in texture and pigmentation
- Months 2-6: Optimal results with complete collagen remodeling
Longevity of results:
- Superficial peels: 1-2 months, require regular maintenance
- Medium peels: 6 months to 2 years depending on indication
- Deep phenol peels: skin changes observed up to 20 years after treatment
Patient satisfaction with chemical peels
Chemical peels maintain constant popularity thanks to their versatility, relative simplicity and favorable cost-effectiveness ratio.
Overall satisfaction rate: High for peels appropriate to the indication. Studies show that patients particularly appreciate improvement in radiance, texture and skin tone uniformity.
Factors influencing satisfaction:
- Appropriate selection of peel type for the indication
- Realistic expectations established during consultation
- Adequate skin preparation
- Rigorous post-treatment care
- Strict sun protection
Superficial to medium peels generally offer the best balance between visible results and social acceptability of recovery time.
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Side effects and complications of chemical peels
Complications are generally related to injury depth — deeper peels offer more marked results but with increased incidence of complications.
Frequent and expected (all peels):
- Erythema (100%) — variable duration depending on depth
- Burning sensation during and after application
- Desquamation (intensity proportional to depth)
- Temporarily increased skin sensitivity
Superficial peels:
- Itching
- Dryness
- Contact dermatitis (irritant or allergic)
- Post-inflammatory hyperpigmentation (PIH) — more frequent in phototypes IV-VI
Medium and deep peels (in addition to above):
- Edema: occurs within 24-72h, more marked with medium/deep peels, particularly periorbital
- Milia: small white cysts, frequent, resolve spontaneously or by extraction
- Infection: bacterial (Staphylococcus, Pseudomonas), viral (herpes simplex), fungal (Candida)
- Herpetic reactivation: occurs in patients with history, hence importance of antiviral prophylaxis
- Scars: rare with appropriate technique, more frequent if infection or picking
Rare but serious complications:
- Permanent hypopigmentation (increased risk with deep peels)
- Demarcation lines (particularly with medium/deep peels if poor feathering technique)
- Ectropion (deep periorbital peels)
- Systemic toxicity (phenol, high concentration TCA over large area)
PIH risk factors:
- Dark phototypes (Fitzpatrick IV-VI)
- Post-peel sun exposure
- Absence of pigment preparation
- Excessive inflammation
- Peel too aggressive for skin type
Chemical peels compared to other technologies
Versus fractional lasers (Fraxel):
- Peels: Less expensive, simpler technique, excellent for superficial pigmentation
- Fraxel: Better for deep collagen remodeling and scars, safer for all phototypes
Versus ablative CO₂ laser:
- Medium peels: Similar recovery (7-10 days), less tightening effect
- CO₂: More spectacular results for wrinkles and laxity, but increased risks
Versus RF microneedling:
- Peels: Excellent for pigmentation and superficial texture, "top-down" approach
- RF microneedling: Better for deep dermal remodeling without affecting surface, "bottom-up" approach
Unique advantages of peels:
- Versatility (multiple agents for multiple indications)
- Simplicity and accessibility
- Generally lower cost
- Excellent for epidermal pigmentation
- Well-established techniques with decades of clinical experience
How to optimize your results with a chemical peel
Skin preparation (2-4 weeks): Non-negotiable, particularly for dark skin and melasma treatment. Standard protocol: SPF 50 sun protection, 2-4% hydroquinone, 0.025-0.05% tretinoin, 10% glycolic acid.
Absolute sun protection: Before, during and after the series of peels. UV exposure is the main cause of PIH and compromises results.
Antiviral prophylaxis: If history of herpes labialis: acyclovir 400mg 3x/day or valacyclovir 1g 2x/day, starting the day of the peel and continuing 7-14 days.
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Post-peel care:
- Gentle cleansing with mild soap or soap-free cleanser
- Intensive hydration with occlusive creams
- Antibiotic ointment if crusts (prevent bacterial infection)
- Do not scratch, peel, rub or scrub the skin
- Strict sun protection until complete healing
Avoid: Retinoids, acids, exfoliants until complete desquamation. New sun exposure for at least 4-6 weeks.
Feathering technique: For medium/deep peels, the agent must be "feathered" at the edges with lower concentration to avoid visible demarcation lines.
Chemical peels combined with other treatments
Peels integrate well into multi-modal rejuvenation protocols.
With topical products: Combination of superficial peels (50-68% glycolic acid, 20-30% salicylic acid) with topical agents (2-4% hydroquinone, 10% glycolic acid, 0.05% tretinoin) shows superior efficacy for PIH in dark skin.
With injectables: Peels for overall skin quality + botulinum toxin for dynamic wrinkles + fillers for volumetric restoration = holistic approach.
With lasers/energy devices: Combinations possible but require appropriate spacing to avoid over-treatment. Generally 4-6 weeks between different modalities.
Critical timing: Always treat in cranio-caudal order (forehead → periorbital area → nose → cheeks → perioral area → chin) to precisely control depth and avoid excessive agent accumulation.
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Choosing a qualified practitioner for a chemical peel
Although superficial peels are relatively safe, all peels are technique-dependent. Potentially serious complications can occur with poor patient selection, inappropriate technique or inadequate post-treatment care.
Look for a practitioner who:
- Has appropriate medical training and substantial experience in chemical peels
- Carefully evaluates your skin type (Fitzpatrick scale) and adapts the protocol
- Performs a sensitivity test in the retro-auricular area before complete peel
- Knows the precise endpoints for each agent
- Uses authentic medical-grade agents (NOT "at-home" products)
- Understands facial anatomy, particularly dangerous areas
- Openly discusses risks, particularly PIH for dark skin
- Prescribes appropriate skin preparation and antiviral prophylaxis if necessary
- Ensures post-treatment follow-up and availability to manage complications
Special attention for dark skin: Medium and deep peels must be performed with great caution in phototypes IV-VI. Deep peels are generally NOT recommended for Indian/dark skin.
Chemical peel prices in Belgium
Rates vary considerably depending on the type of agent, depth, treated area and practitioner expertise.
Superficial peels:
- Glycolic acid (20-70%): €80 to €150 per session
- Salicylic acid (20-30%): €100 to €180 per session
- Mandelic acid (10-40%): €120 to €200 per session
Medium peels:
- 35% TCA: €200 to €400 per session
- Jessner's solution + TCA: €250 to €450 per session
- Modern combination peels: €200 to €500 per session
Packages: Many practitioners offer packages of 4-6 sessions with a 10-20% discount on the total cost. To treat acne or hyperpigmentation, a package is generally more economical.
Non-facial areas:
- Neck/décolletage: +€50 to €100 additional
- Hands: €150 to €300 per session
These treatments are aesthetic and not reimbursed. The total cost for a complete series can reach €400 to €2000 depending on the indication. Always ask for a personalized treatment plan and quote during consultation.
Important note: never use chemical peeling products at home without professional supervision. High-concentration acids can cause severe burns, infection, pigment changes, and permanent scarring.
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