3 Peel depths (superficial, medium, deep) each with distinct evidence, downtime, and risk profiles (most clinics don't explain the differences)
6 Sessions of superficial glycolic acid shown to significantly improve melasma: meaning you need consistent commitment, not a one-and-done treatment
30% Salicylic acid concentration is the gold standard for acne (Sarkar et al., 2024), with strong evidence behind it

The three peel depths explained

Superficial peels hit only the top layer (epidermis). Glycolic acid, salicylic acid, lactic acid. Minimal to no visible peeling. No downtime. You can do them repeatedly and the evidence is strongest here.

Medium-depth peels penetrate deeper (upper dermis). TCA at 35% concentration typically. You'll see visible peeling for 5-7 days. You need to avoid sun. Recovery is real, and this is where most clinics oversell without explaining the risk-benefit trade-off.

Deep peels (phenol-based) reach deeper still. Need anaesthesia. Serious risks including permanent scarring and pigmentation changes. Only done by physicians in actual clinical settings, and often the risks outweigh the benefits.

Research Note

A 2024 systematic review by Sarkar et al. in the Journal of Clinical and Aesthetic Dermatology found that serial superficial glycolic acid and salicylic acid peels showed consistent improvements in melasma severity scores across multiple controlled trials, particularly when combined with topical agents. The review found 6 sessions over 3–4 months produced the most consistent results.

What works for what

Acne: 30% salicylic acid is the gold standard. Strong evidence. Safe across all skin tones.

Melasma and discoloration: Glycolic acid peels work. Multiple RCTs show improvement. Needs repeated sessions (usually 6 over 3-4 months).

Fine lines and texture: Glycolic acid helps. Evidence is solid but improvements are modest.

Severe photoaging: Deeper peels have better evidence but much higher risk. The risk-benefit changes dramatically with depth.

Important for Darker Skin Tones

Women with Fitzpatrick skin types IV–VI face a significantly higher risk of post-inflammatory hyperpigmentation (PIH) from medium and deep peels: potentially leaving darker patches than the original concern. Superficial peels are generally considered safer for darker skin tones. Always consult a dermatologist with specific experience treating your skin type before booking any peel.

What clinics don't tell you

"Chemical peel" ranges from a gentle at-home formula to hospital-grade deep peels. Most cosmetic clinics don't specify what depth or concentration they're using. That's a red flag.

Sun exposure after a peel drives dark spots, especially for darker skin tones. You need strict sun avoidance. Retinol and other actives should pause 1-2 weeks before. Clinics don't always ask about this. And peels are off-limits in pregnancy, active infections, recent Accutane, and certain skin conditions.

Questions to ask before booking

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When to see a dermatologist first

A dermatology consultation before any medium or deep peel is strongly advisable: particularly for persistent melasma, rosacea, or darker skin tones. A dermatologist can assess whether a peel is appropriate, recommend the right depth and agent, and supervise treatment safely.

Medical Disclaimer: This article is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

References

  1. Sarkar R, Garg VK, Jain A. Chemical Peels for Melasma: A Systematic Review. J Clin Aesthet Dermatol. 2024;17(3). PubMed
  2. Expert Consensus on the Clinical Application of Chemical Peels. Int J Dermatol Venereol. 2024;7(4). Full text
  3. Fischer TC, Perosino E, Poli F, et al. Glycolic acid peel therapy: a current review. Dermatol Surg. PMC3875240. PMC