Exfoliation 101

Exfoliation is the process of removing dead skin cells from the surface. There are two types: chemical (using acids or enzymes) and physical (scrubs, brushes). Chemical exfoliation is generally gentler and more controlled than physical.

AHAs are water-soluble acids that work on the skin's surface. They are best for dry, sun-damaged, or dull skin. Common AHAs: • Glycolic Acid (small molecule, most potent, best for anti-ageing) • Lactic Acid (larger molecule, gentler, also hydrating) • Mandelic Acid (largest, best for sensitive skin) • Start with 5–10%, 2–3x/week.

Salicylic Acid is the only common BHA. It is oil-soluble, meaning it can penetrate deep into pores to clear sebum and debris. Best for oily, acne-prone, or congested skin. Use 0.5–2%, 2–3x/week.

• Normal skin: 2–3x/week • Oily/acne-prone: up to 3–4x/week with BHA • Dry/sensitive: 1–2x/week with gentle AHA (lactic or mandelic) • Retinoid users: reduce to 1x/week or stop exfoliation during retinoid adjustment (first 4–6 weeks) More is NOT better — over-exfoliation damages the skin barrier.

• Redness, stinging, burning sensation • Shiny, waxy appearance (stripped barrier) • Increased breakouts (not purging — actual breakouts) • Dehydrated, tight, peeling skin • Products that normally feel fine now sting If you notice these, stop all exfoliation and focus on barrier repair (gentle cleanser, moisturiser, SPF) for 2–4 weeks.

Physical exfoliation uses mechanical action — scrubs, brushes, konjac sponges, washcloths. Chemical exfoliation uses acids (AHAs, BHAs) or enzymes (papain, bromelain) to dissolve the bonds holding dead skin cells together. When physical exfoliation is appropriate: • Very minimal physical exfoliation with soft cloths or gentle enzyme masks is fine for normal-to-oily skin • Konjac sponges offer very gentle daily mechanical exfoliation • Sugar scrubs on the body are fine — skin there is thicker • Harsh facial scrubs (walnut shell, sugar with pressure) cause micro-tears — avoid When chemical exfoliation wins (almost always for the face): • More controlled, more even exfoliation • Can penetrate to where the issue is (BHA in pores, AHAs in stratum corneum) • No risk of micro-tears • Dose-controllable: adjust concentration and frequency for your skin's response • Better clinical evidence for anti-ageing, acne, and hyperpigmentation Enzyme exfoliation (often overlooked): Papain (papaya), bromelain (pineapple), and pumpkin enzymes directly digest protein bonds between dead skin cells. Gentler than AHAs and a good option for sensitive skin. Typically found in masks rather than leave-on products.

Not all acid concentrations are equal — the right choice depends on your skin's experience and tolerance: Glycolic Acid: • 5–8%: Beginner range, safe for daily use in some formulations • 10%: Standard effective leave-on concentration • 15–20%: Advanced, use 1–2x/week, not daily • 30%+: Professional peel territory only Lactic Acid: • 5%: Very gentle, suitable for daily use and even sensitive skin • 10%: Moderate exfoliation with mild anti-ageing • 12%: The upper limit of general consumer-use leave-ons Salicylic Acid: • 0.5–1%: Gentle, suitable for sensitive or acne-prone beginners • 2%: The most studied and effective OTC concentration for acne • Above 2%: Prescription or professional peel only in many countries How to level up safely: If you've been using a lower concentration for 8+ weeks with no issues and want stronger results, increase by one concentration tier and restart 2x/week frequency for 4 weeks before moving to more frequent use.

Exfoliation carries additional risks for people with medium to dark skin tones (Fitzpatrick III–VI). Post-inflammatory hyperpigmentation (PIH): Darker skin has more reactive melanocytes. Any irritation — including over-exfoliation — can trigger PIH, leaving dark marks that may take months to fade. The irony: if you're exfoliating to fade marks, over-exfoliation creates more. What to do differently: • Choose mandelic acid over glycolic for first-time use — its larger molecule is gentler and it has mild antibacterial properties that help acne-driven PIH • Never exceed 10% glycolic acid • Always use SPF 50+ — UV exposure worsens any existing hyperpigmentation • Introduce any exfoliant at maximum 2x/week for the first 4 weeks • Pair with niacinamide which helps fade pigmentation through a completely different pathway • If irritation occurs at any stage, stop immediately — the resulting PIH will be harder to treat than the original issue