Physical exfoliation — scrubs, brushes, rough cloths — works by mechanical abrasion. It removes surface dead cells, but it does so unpredictably, often causes microtears in the skin, and provides no benefit below the surface. Chemical exfoliants are more precise, more effective, and safer when used correctly.
AHAs (alpha hydroxy acids) — glycolic, lactic, mandelic acid — are water-soluble and work on the skin’s surface. They dissolve the bonds holding dead skin cells together, improving texture, brightness, and fine lines. Best for dry, dull, or aging skin.
BHAs (beta hydroxy acids) — primarily salicylic acid — are oil-soluble. They penetrate through sebum into the pore lining. Best for oily, acne-prone, or congested skin with enlarged pores.
PHAs (polyhydroxy acids) — gluconolactone, lactobionic acid — are larger molecules that work more slowly and gently. Best for sensitive skin that cannot tolerate AHAs or BHAs.
What to Avoid
Do not use physical scrubs with chemical exfoliants on the same day. Do not layer multiple acids without building tolerance first. Do not use AHAs or BHAs before or after retinol in the same routine (use on alternate nights). Always use SPF the morning after chemical exfoliation — AHAs significantly increase UV sensitivity.
Over-exfoliation is the most common skincare mistake. Shiny, tight, sensitive skin that looks “too smooth” is barrier damage. More is not better.
Best Overall: Paula’s Choice Skin Perfecting 2% BHA Liquid Exfoliant
The Paula’s Choice 2% BHA Liquid ($34 for 4oz) is the most studied, most recommended BHA exfoliant in the category. The 2% salicylic acid in a pH-optimized formula (3.2–3.8) penetrates pores effectively, dissolves plugs, reduces congestion, and smooths uneven texture.
- Acid: Salicylic acid 2% (BHA)
- Format: Lightweight liquid applied with a cotton pad
- Best for: Oily skin, clogged pores, blackheads, bumpy texture, mild acne
- Use frequency: Start 2–3x per week; work up to daily if tolerated
- SPF required next morning: Yes
- Verdict: The most reliable BHA on the market. The low pH ensures actual efficacy (many drugstore BHAs are pH-too-high to work). Worth every cent.
Best AHA: The Ordinary Glycolic Acid 7% Toning Solution
The Ordinary Glycolic Acid 7% Toning Solution ($10 for 8oz) delivers pharmaceutical-grade glycolic acid at a concentration that produces real results without being aggressive. Glycolic is the smallest AHA molecule — it penetrates most effectively — and 7% is strong enough to visibly improve skin texture and brightness over 4–6 weeks.
- Acid: Glycolic acid 7% (AHA)
- Format: Toning solution applied with a cotton pad
- Best for: Dull, uneven skin tone, fine lines, rough texture, dry skin
- Use frequency: 3–4x per week, evenings only
- SPF required next morning: Yes, critical with AHAs
- Note: Do not use around the eye area. Can cause mild tingling — this is normal at this concentration.
- Verdict: The best-value AHA exfoliant available. The 8oz size makes it genuinely cheap per use.
Best for Sensitive Skin: First Aid Beauty Facial Radiance Pads
The First Aid Beauty Facial Radiance Pads ($38 for 60 pads) use a combination of lactic acid (10%) and glycolic acid (3%) — the gentler, larger AHA molecules — with calming oat extract and allantoin to prevent irritation. Pre-soaked pads make dosing consistent.
- Acids: Lactic 10% + glycolic 3% (AHA blend)
- Format: Pre-soaked pads
- Best for: Sensitive skin, beginners to chemical exfoliation, dry and dull skin
- Use frequency: 2–3x per week
- SPF required next morning: Yes
- Verdict: The best entry point for chemical exfoliation for those who react to everything. The lactic acid is fundamentally gentler than glycolic while still effective.
Best Combination AHA+BHA: COSRX AHA 7 Whitehead Power Liquid + BHA Blackhead Power Liquid
The COSRX AHA/BHA duo ($20 each for 3.4oz) are the most popular exfoliants in the Korean beauty market. The AHA formula uses 7% glycolic acid for surface smoothing; the BHA uses 4% betaine salicylate (a gentler BHA alternative to standard salicylic). Using them on alternating nights addresses both surface texture and pore congestion without the aggression of using both simultaneously.
- Acids: Glycolic 7% (AHA) / Betaine salicylate 4% (BHA)
- Format: Liquid toners applied with hands or cotton
- Best for: Combination to oily skin, alternating concerns
- Use frequency: Alternate nights
- SPF required next morning: Yes
- Verdict: The best option for combination skin dealing with both dullness and congestion. The betaine salicylate is notably gentler than sodium salicylate for sensitive-oily types.
Best Budget: Stridex Maximum Strength Pads (2% Salicylic Acid)
The Stridex Maximum Strength Pads ($10 for 90 pads) are the OG drugstore chemical exfoliant. 2% salicylic acid in pre-soaked pads, pH approximately 3.0. They work. The texture of the pad provides light mechanical exfoliation simultaneously, which makes them slightly more aggressive than the Paula’s Choice liquid.
- Acid: Salicylic acid 2% (BHA)
- Format: Pre-soaked textured pads
- Best for: Oily, acne-prone skin — the best acne-fighting chemical exfoliant under $15
- Use frequency: 2–3x per week to start; skin-dependent increase
- SPF required next morning: Yes
- Note: The formulation includes SD alcohol which can be drying for some skin types. If dryness is an issue, switch to Paula’s Choice.
- Verdict: Unbeatable for the price. If budget is the primary concern, this is your starting point.
Quick Comparison
| Product | Acid Type | Concentration | Price | Best For |
|---|---|---|---|---|
| Paula’s Choice BHA Liquid | Salicylic (BHA) | 2% | $34 | Pores, oily, congested |
| The Ordinary Glycolic 7% | Glycolic (AHA) | 7% | $10 | Dull, dry, rough texture |
| FAB Radiance Pads | Lactic + glycolic (AHA) | 10% + 3% | $38 | Sensitive skin beginners |
| COSRX AHA/BHA duo | Glycolic + betaine (AHA+BHA) | 7% / 4% | $40 | Combination skin |
| Stridex Maximum | Salicylic (BHA) | 2% | $10 | Acne-prone, budget |
Building a Chemical Exfoliation Routine
Beginner protocol: 1–2x per week, evenings only, after cleansing. No other actives that night. SPF next morning without fail.
Intermediate: 3x per week AHA or BHA (not both on the same night). Alternate with retinol nights.
Advanced: AHA and BHA on alternating evenings (not simultaneously). Retinol 2–3 nights on the remaining days.
Never go past the point where your skin feels tight, sensitive, or looks shiny and almost raw. That is barrier compromise, not progress.
The Bottom Line
If you have oily or congested skin: Paula’s Choice 2% BHA Liquid is the gold standard. If you have dry or dull skin: The Ordinary Glycolic Acid 7% at $10 is the best value active ingredient in skincare. If your skin is sensitive: start with FAB Radiance Pads and build from there. Use SPF. No exceptions.
