Chemical peel guide: superficial, medium, and deep peels — what's right for your skin

Chemical peels are one of the oldest and most evidence-backed treatments in medical aesthetics — and one of the most misunderstood. The spectrum runs from gentle monthly maintenance peels to deep treatments that require 2 weeks of healing. Here's how to navigate the categories.

How chemical peels work

All chemical peels work by applying an acid solution to the skin, which dissolves the bonds between dead skin cells (causing exfoliation) and, at higher concentrations, damages and destroys deeper skin layers to stimulate new skin growth.

The depth of peel determines:
Which skin concerns it treats
How much downtime it causes
The risk profile for different skin tones

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Superficial peels

Penetration depth: Epidermis only (stratum corneum to lower epidermis)

Common acids: Glycolic acid (alpha-hydroxy acid), lactic acid, mandelic acid, salicylic acid (beta-hydroxy acid), lower-concentration TCA (10–20%)

Glycolic acid peels (10–50%)

The workhorse superficial peel. Glycolic acid is the smallest AHA molecule — it penetrates well and exfoliates effectively.

What it treats:
Mild dullness and uneven texture
Fine surface lines
Mild hyperpigmentation and melasma (with caution — see below)
Acne and enlarged pores (increases cellular turnover)

Downtime: None to mild. Some redness for a few hours; mild peeling over 2–4 days at higher concentrations.

Skin tone: Glycolic at standard concentrations is generally safe for Fitzpatrick I–IV. Higher concentrations require caution in darker skin tones. Melasma caution: Aggressive glycolic peels can trigger post-inflammatory hyperpigmentation in patients with melasma or Fitzpatrick IV–VI skin — a lower-strength or more targeted approach (mandelic, tranexamic acid preparations) is often preferred.

Sessions: Often done as a monthly series of 4–6 peels.

Cost: $75–$200 per session.

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Salicylic acid peels (15–30%)

A beta-hydroxy acid with lipophilic (oil-soluble) properties — it penetrates into pores more effectively than AHAs.

Best for: Acne-prone skin, oily skin, blackheads. The pore-penetrating property makes it the preferred superficial peel for congestion.

Skin tone: Generally well-tolerated across skin tones, including Fitzpatrick IV–V. Lower inflammation risk than glycolic in melanin-rich skin.

Downtime: Minimal. Some mild flaking.

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Mandelic acid peels

A larger AHA molecule than glycolic — slower penetration, gentler exfoliation, less irritation.

Best for: Sensitive skin, rosacea-prone skin, patients with Fitzpatrick III–VI who want an AHA peel. One of the safest peels for darker skin tones.

What it treats: Similar to glycolic but more slowly. Good for mild hyperpigmentation, texture, acne.

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Lactic acid peels

Derived from milk; hydrating as well as exfoliating. The gentlest of the common AHA peels.

Best for: Dry, sensitive skin; very gentle texture improvement. Not ideal as the primary treatment for significant concerns.

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Medium-depth peels

Penetration depth: Full epidermis into the papillary dermis

Common acid: TCA (trichloroacetic acid) 20–35%; Jessner's solution + TCA combination; VI Peel (combination formula)

TCA peels (20–35%)

The reference medium-depth peel. At 25–35%, TCA reaches the papillary dermis, stimulating significant collagen remodeling and producing meaningful improvement in skin aging, sun damage, and scarring.

What it treats:
Moderate sun damage and solar lentigines
Moderate fine lines and texture
Melasma (with caution — TCA can worsen melasma if not properly managed)
Acne scarring (surface improvement; not deep ice-pick scars)
Superficial seborrheic keratoses

Downtime: 5–7 days of active peeling. Skin forms a brown "frost," then darkens and peels over 5–7 days. Redness for 2–4 weeks. Return to work typically 7–10 days.

Skin tone: TCA at 25–35% can be used in Fitzpatrick III–IV with care and proper pre-treatment (hydroquinone preparation for 4 weeks). Fitzpatrick V–VI: significant hyperpigmentation risk; lower concentrations or different approaches preferred.

Sessions: Often 1–2 treatments per year for maintenance; single treatment for significant correction.

Cost: $300–$600 per session.

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VI Peel (and similar combination formulas)

The VI Peel (Vitality Institute) is a pre-formulated combination peel containing TCA, retinoic acid, salicylic acid, phenol, and vitamin C. It's applied as a system and has gained popularity because:
It's designed for broader skin-tone safety (including Fitzpatrick IV–VI)
The multi-acid combination acts at different depths
It's consistent and easy to apply in a med spa setting

Results: Similar to medium-depth TCA peels but with a slightly different profile. Multiple formulas exist (VI Peel, VI Peel Precision, VI Peel Precision Plus for melasma/hyperpigmentation).

Downtime: 5–7 days of peeling.

Cost: $200–$400 per treatment.

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Deep peels

Penetration depth: Reticular dermis (full dermal layer)

Acid: Phenol (carbolic acid), typically in the Gordon-Baker phenol formula or similar

Phenol peels

The most aggressive chemical peel — dramatic results, significant systemic risk, rare at most med spas.

What it treats:
Severe sun damage and dyschromia
Deep rhytids (perioral lines, severe facial wrinkles)
Pre-malignant lesions

Who performs it: Dermatologists or plastic surgeons in a clinical setting with cardiac monitoring. Phenol is cardiotoxic if absorbed too quickly — must be applied slowly with careful timing.

Downtime: 10–14 days of healing. Skin weeps, crusts, and heals over 2 weeks. Redness for 3–6 months. Permanent lightening of treated skin.

Skin tone: Phenol is generally only appropriate for Fitzpatrick I–III due to permanent depigmentation risk in darker skin.

This is not a med spa treatment in most settings. Mention it for completeness — patients asking about "deep peels" should know this exists and requires a medical specialist.

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Peel comparison table

| Peel type | Depth | Downtime | Fitzpatrick safety | Best for |
|---|---|---|---|---|
| Glycolic 20–40% | Epidermis | None–mild | I–IV (caution melasma) | Texture, acne, mild pigment |
| Salicylic 15–30% | Epidermis (pores) | Minimal | I–V | Acne, oily/congested skin |
| Mandelic | Epidermis (slow) | Minimal | I–VI | Sensitive/dark skin, mild concerns |
| TCA 20–35% | Epidermis + papillary dermis | 5–7 days | I–IV (caution) | Sun damage, aging, moderate scars |
| VI Peel (combo) | Epidermis + papillary dermis | 5–7 days | I–VI (designed for) | Hyperpigmentation, broad use |
| Phenol | Full dermis | 10–14 days | I–III only | Severe aging, deep wrinkles |

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Pre-peel preparation

For medium-depth peels or any peel on Fitzpatrick III+ skin:
Topical hydroquinone 4% for 4 weeks pre-peel (reduces PIH risk)
Tretinoin (retinoic acid) for 2–4 weeks pre-peel (pre-conditions skin, accelerates healing) — stop 5–7 days before the peel
Daily SPF 30+ in the 4 weeks before

For superficial peels: No prep required for most patients, though SPF is always recommended.

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Post-peel care

Moisturize and protect: Petrolatum or non-occlusive barrier moisturizer during peeling phase
Absolutely no sun exposure: UV during healing causes PIH
SPF 30+ minimum once re-epithelialized
No picking, peeling, or rubbing: Removing peeling skin before it's ready disrupts healing and causes scarring
No retinoids until fully healed (typically 2–4 weeks for medium peels)

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Questions to ask before booking

For my skin tone (Fitzpatrick type), what depth and acid type do you recommend?
Do I need a pre-peel hydroquinone protocol, and for how long?
For melasma: is a peel appropriate for me, or could it worsen my pigmentation?
What is the realistic downtime for the specific peel you're recommending?
If I have a history of cold sores, do I need antiviral prophylaxis before a medium-depth peel?

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