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Glycolic vs Lactic vs Salicylic Acid: Which Exfoliant Suits Your Skin

Compared by Kath · 10/29/2026

HMMMM SAYS

Glycolic acid is the most versatile workhorse of the three.

If you're trying to figure out which exfoliating acid class belongs in your routine, glycolic edges ahead on chemistry and cost. At ~76 Da (the smallest AHA per published molecular data), it penetrates most deeply among the three, and The Ordinary's 7% Toner delivers that at $1.69/fl oz on Sephora — unbeatable value. That said, if your skin skews sensitive, lactic's larger ~90 Da molecule and built-in hyaluronate (per INCI Decoder) make it the smarter surface exfoliant. Salicylic's oil-solubility at 138 Da is a genuinely different tool — irreplaceable for congested, oily skin, just pricier per ounce.

KBy Kath · 10/29/2026 · beauty
Made byKathwith hmmmm

How they scored

FactorGlycolic Acid AHA ExfoliantLactic Acid AHA ExfoliantSalicylic Acid BHA Exfoliant

Active ingredient type

weight 38%

978

Best-suited skin types

weight 32%

778

Price per fluid ounce

weight 20%

1096

Gentleness & irritation profile

weight 10%

596
Total8.2/107.6/107.4/10

Each option in detail

🥇Rank 1·$8–$18

Glycolic Acid AHA Exfoliant

8.2out of 10

What's good

  • ✓~76 Da molecular weight — smallest of the three AHAs, per The INKEY List's published molecular comparison.
  • ✓The Ordinary 7% Toner is $13.50 for 8 fl oz on Sephora ($1.69/fl oz) — lowest normalized cost of all three options.
  • ✓Water-soluble AHA; 7% concentration (labeled on The Ordinary's active ingredient declaration) sits at the effective OTC range.

Watch out for

  • ✗Smallest molecule penetrates most deeply — The INKEY List notes glycolic is 'most likely to tingle uncomfortably on application.'
  • ✗Not oil-soluble; cannot follow sebum into the pore lining the way salicylic acid does, per basic AHA/BHA chemistry.
  • ✗Labeled 7% concentration may require pH buffering for efficacy; The Ordinary's formula lists Sodium Hydroxide as a pH adjuster on INCI Decoder.
🥈Rank 2·$7–$38

Lactic Acid AHA Exfoliant

7.6out of 10

What's good

  • ✓~90 Da molecule — larger than glycolic, works closer to the skin surface for a shallower, gentler exfoliation per The INKEY List molecular data.
  • ✓INCI Decoder lists Sodium Hyaluronate Crosspolymer in The Ordinary Lactic Acid 5% + HA formula — a humectant paired with the acid on the label.
  • ✓The Ordinary 5% + HA retails at $8.10 on Sephora for 1 fl oz ($8.10/fl oz) — competitive for a serum format with added HA.

Watch out for

  • ✗Larger molecule means shallower penetration than glycolic — less suited for deeper texture work per AHA chemistry.
  • ✗10% higher-strength variant (The Ordinary Lactic Acid 10% + HA) jumps to ~$7–$38 range, widening cost variability.
  • ✗SkinSAFE notes The Ordinary Lactic Acid 5% + HA is 91% Top Allergen Free — meaning ~9% of listed ingredients overlap with common allergen lists.
🥉Rank 3·$15–$35

Salicylic Acid BHA Exfoliant

7.4out of 10

What's good

  • ✓138.12 g/mol and oil-soluble (lipophilic) per salicylicacid.org — the only one of the three that can penetrate sebum-filled pore channels.
  • ✓Paula's Choice 2% BHA Liquid is labeled fragrance-free and alcohol-free on the Sephora product page — both manufacturer-stated claims.
  • ✓OTC maximum concentration of 2% salicylic acid (as listed in the active ingredient on Paula's Choice labeling) represents the full permitted cosmetic dose.

Watch out for

  • ✗Paula's Choice 2% BHA 4 fl oz retails at $37 on Dermstore ($9.25/fl oz) — highest normalized price of the three options.
  • ✗Paula's Choice mini (1 fl oz) is $15 on Sephora ($15/fl oz) — significantly higher per-ounce cost than the full-size, punishing trial purchasers.
  • ✗BHA's keratolytic action can strip surface lipids; salicylicacid.org notes optimal cosmetic pH range is 3.0–4.0, which may affect the skin barrier with overuse.

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Sources

Facts in this comparison are drawn from these references. Verify anything that matters for your situation.

  1. [1]The Ordinary Glycolic Acid 7% Toning Solution — Sephora— Sephora
  2. [2]The Ordinary Lactic Acid 5% + HA Ingredients — INCI Decoder— INCI Decoder
  3. [3]Paula's Choice Mini Skin Perfecting 2% BHA Liquid Exfoliant — Sephora— Sephora
  4. [4]Salicylic Acid Molecular Weight & Mechanism — salicylicacid.org— salicylicacid.org
  5. [5]AHA Molecular Weights Comparison — The INKEY List Blog— The INKEY List

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