6.3 Exfoliation: Mechanical, Chemical Peels & Microdermabrasion

6.3 Exfoliation: Mechanical, Chemical Peels & Microdermabrasion

Quick Answer: Exfoliation removes dead cells from the stratum corneum either mechanically (scrubs, brushes, microdermabrasion) or chemically (AHAs, BHA, enzymes). New York estheticians are limited to superficial, light chemical peels — medium and deep peels are medical procedures outside the scope of an esthetics license — and every chemical service requires a patch test and a screen for universal contraindications first.

Mechanical Exfoliation

Mechanical exfoliation physically removes dead skin cells through friction or abrasion, rather than dissolving the bonds between cells the way a chemical exfoliant does.

• Manual scrubs/granular exfoliants — a cream or gel base loaded with small particles (jojoba beads, rice powder, and similar ingredients) that the esthetician massages over the skin to slough off dead cells by hand.
• Brush/rotary machines — a motorized rotating brush head that provides deeper, more even mechanical exfoliation and cleansing than a manual scrub, with pressure and speed adjustable to skin sensitivity.
• Microdermabrasion — a machine-based technique that physically abrades the stratum corneum using one of two delivery methods:
  • Crystal microdermabrasion propels fine crystals (commonly aluminum oxide) across the skin under vacuum pressure; the crystals abrade the surface and are vacuumed away along with the exfoliated debris.
  • Diamond-tip microdermabrasion uses a wand tipped with a diamond-textured abrasive surface, moved directly across the skin under suction, without loose crystals to contain or vacuum separately.

Because mechanical exfoliation relies on physical friction, it is generally avoided on active acne, broken capillaries, or already irritated or inflamed skin, where added friction can spread bacteria or worsen inflammation.

Chemical Exfoliation

Chemical exfoliants dissolve the bonds holding dead surface cells together, allowing them to shed without mechanical friction.

Glycolic acid has the smallest molecular size of the common AHAs, which is part of why it penetrates efficiently and is a frequent starting point for AHA treatments; lactic acid is slightly gentler and also has humectant, moisture-binding properties. Salicylic acid's oil solubility is the key distinguishing fact tested on exams — it is the option that works inside the follicle rather than only on the surface, which is why it is the standard choice for oily and acne-prone skin.

Peel Depth: Superficial, Medium & Deep

Chemical peels are classified by how deeply they penetrate the skin:

1. Superficial (light) peels — affect only the epidermis and stratum corneum. Minimal downtime, at most mild redness.
2. Medium peels — penetrate into the papillary dermis. Produce visible peeling, more significant downtime, and a stronger risk profile.
3. Deep peels — penetrate into the reticular dermis. Produce dramatic resurfacing but carry serious risks such as scarring and pigment changes, and are performed only under physician supervision.

New York limits a licensed esthetician to superficial, light chemical peels only. Medium and deep peels involve deeper tissue penetration and a higher complication risk and typically require a physician's oversight — they fall outside the esthetics scope of practice and into a medical spa or physician-supervised setting. On the written exam, a scenario describing a deep or medically supervised peel is testing whether the candidate recognizes it as outside scope, not testing peel technique.

Patch Testing & Universal Contraindications

Before performing any chemical exfoliation service, apply a small patch test of the product to an inconspicuous area, commonly behind the ear or on the inner forearm, and wait the manufacturer-recommended time to check for a reaction before proceeding to a full-face application.

Chemical exfoliation services are avoided when the client has:

• Broken or open skin in the treatment area — the barrier is already compromised, and adding an acid increases irritation and infection risk.
• An active skin infection, bacterial, fungal, or viral, including active cold sores — chemical exfoliation can spread the infection.
• Recent use of isotretinoin (Accutane) — this medication significantly thins the skin, and combining it with a chemical peel is a well-known cause of severe irritation and scarring; the esthetician should confirm the client is fully clear of it before proceeding.
• Pregnancy, for certain acids — some ingredients call for extra caution or avoidance during pregnancy, so a careful consultation and, when in doubt, a more conservative choice such as an enzyme peel is appropriate.
• Sunburned skin — the skin is already inflamed and barrier-compromised, so exfoliation is postponed until it has fully healed.

Screening for these universal contraindications during consultation, before any product touches the skin, is one of the single most exam-relevant safety habits in this chapter.