Informed Skin›AHA Exfoliants

Products

AHA Exfoliants

Glycolic acid / lactic acid / mandelic acid

Chemical exfoliation for texture and tone

Fine Line WrinklesHyperpigmentationDark SpotsPore SizeLoss of Collagen
Safe for skin types
Safe forFitzpatrick I–III at standard OTC concentrations (5–10%)
Use cautionFitzpatrick IV–V: PIH risk at higher concentrations or frequent use; test carefully
Avoid ifFitzpatrick VI at high concentrations; active eczema; sunburned skin

AHA exfoliants accelerate cell turnover and can trigger post-inflammatory hyperpigmentation if overused in darker skin types. Low concentrations, infrequent use, and mandatory daily SPF reduce risk significantly.

In plain English

AHA exfoliants (glycolic, lactic, and mandelic acid are the most common) chemically dissolve the bonds holding dead skin cells on the surface, revealing fresher skin underneath. Unlike scrubs, they work invisibly without friction. With consistent use they smooth texture, fade pigmentation, and have some collagen-boosting effects at higher concentrations. The trade-off is increased sun sensitivity, so SPF the next morning is non-negotiable.

Top-rated products

Sourced via EWG Skin Deep, one of the scientific databases used by the Yuka app to evaluate cosmetic ingredient safety.

Glycolic Acid 7% Toning Solution

The Ordinary

Skin Perfecting 8% AHA Gel Exfoliant

Paula's Choice

Glycolic Renewal Smoothing Lotion

Dermalogica

The science

Alpha-hydroxy acids (AHAs) including glycolic acid (C2, smallest molecule, deepest penetration), lactic acid (C3, gentler, also a humectant), and mandelic acid (C8, largest, slowest penetration for sensitive skin) exfoliate by disrupting calcium-dependent corneodesmosomes, the protein bridges holding dead skin cells together, accelerating desquamation without abrasion. At concentrations above 8% and pH below 4, they also have evidence for collagen stimulation and glycosaminoglycan synthesis, extending their mechanism beyond surface-level exfoliation. Multiple RCTs support improvement in photoageing, uneven texture, hyperpigmentation, and mild acne.

Why these scores
Medical PromiseHigher is better
7/10

Good evidence for photoageing, uneven texture, and hyperpigmentation at concentrations above 8%. Glycolic acid has the most data; lactic and mandelic have smaller evidence bases but established mechanisms.

Short-term SafetyHigher is safer
8/10

Well-tolerated at OTC concentrations (up to 10%). Stinging, transient erythema, and over-exfoliation are common with misuse or overuse. Photosensitisation is real and requires morning SPF. Not suitable for broken or acutely inflamed skin.

Long-term SafetyHigher is safer
9/10

No long-term systemic safety concerns at OTC doses. FDA requires sun-sensitivity warnings on AHA products above 10%. Long-term daily use at high concentrations has limited safety data, but moderate-concentration AHAs used 2 to 3 times per week have no documented long-term adverse effects.

Should You Try ThisHigher is better
7/10

A well-evidenced exfoliant tier for improving texture and tone. Best suited to dull, congested, or photodamaged skin. Use 2 to 3 times weekly rather than daily, and never skip morning SPF the following day.

Common misconceptions
✕Myth

“AHA exfoliants thin your skin with prolonged use.”

✓Reality

AHAs thin the dead stratum corneum (which is the intended effect) but with regular use at moderate concentrations, the viable epidermis and dermis are not negatively affected. Some research shows collagen stimulation increases dermal thickness over time.

✕Myth

“Higher concentration means better results.”

✓Reality

pH and formulation matter as much as concentration. A 10% glycolic acid at pH 3.5 is more active than a 20% formulation at pH 5. Concentration alone is a poor predictor of exfoliation efficacy or safety.

✕Myth

“You can use AHAs every day without issue.”

✓Reality

Daily use at effective concentrations commonly leads to over-exfoliation: barrier disruption, tightness, sensitivity, and increased reactivity to other products. Most dermatologists recommend 2 to 3 times per week at working concentrations.

What the evidence firmly supports
  • ✓

    Topical glycolic acid at 5% to 12% applied over 12 to 24 weeks produces measurable improvement in surface roughness, fine lines, and pigmentation versus vehicle in multiple RCTs.

  • ✓

    AHAs work by disrupting calcium-ion-dependent corneodesmosomes, reducing cohesion of the stratum corneum; this mechanism is well-characterised at the molecular level.

  • ✓

    Lactic acid at 12% applied twice daily produced equivalent improvements to glycolic acid in split-face comparisons for photoageing endpoints with less irritation.

  • ✓

    FDA safety studies confirm AHAs increase UV-induced erythema by approximately 18% and require sun-sensitivity labelling above 10% concentration.

Still being studied
  • ?

    Whether the collagen-stimulation mechanism documented at higher concentrations is reproducible at OTC concentrations (below 10%) or requires professional-peel concentrations (20% to 70%).

  • ?

    Mandelic acid's clinical evidence base is smaller than glycolic or lactic acid; head-to-head RCT data for photoageing outcomes is limited.

  • ?

    Long-term effects of daily high-concentration AHA use on the skin microbiome and barrier function.

  • ?

    Whether polyhydroxy acids (PHAs like gluconolactone) provide equivalent exfoliation efficacy to AHAs with genuinely lower irritation.

Key Study

Glycolic acid as a peeling agent in the treatment of photoaged skin: a controlled study

Ditre et al. · Archives of Dermatology · 1996

Randomised double-blind study (n=17) applying 25% glycolic acid cream daily for 6 months demonstrated significant reductions in epidermal and dermal markers of photoageing vs. vehicle, with biopsy-confirmed increases in collagen and mucopolysaccharides.

PubMed ↗  PMID 30027612
Products on the market
BrandManufacturerWhat differentiates itApprovalPricing
The Ordinary Glycolic Acid 7% Toning SolutionDECIEMAffordable entry-level glycolic toner; low pH exfoliation with tasmanian pepperberry to reduce irritationOTC$9 / 240 ml
Paula's Choice Skin Perfecting 8% AHA Gel ExfoliantPaula's Choice8% glycolic acid with green tea antioxidants; widely recommended as a first AHA productOTC$33 / 100 ml
The Inkey List Lactic AcidThe Inkey List10% lactic acid with 0.5% hyaluronic acid; gentler than glycolic, suited to drier or more sensitive skinOTC$12 / 30 ml
REN Ready Steady Glow Daily AHA TonicREN Clean SkincareLactic acid based, fragrance-free daily toner; positioned as gentle enough for daily useOTC$38 / 250 ml
Exuviance Performance Peel AP25ExuviancePhysician-developed 25% polyhydroxy acid blend (PHA/AHA); stronger at-home peel for experienced usersOTC$72 / 30 ml
Quick Facts
DurationDaily/alternate-day use; results in 4–8 weeks
Studies180+
FDA StatusOTC; concentrations >10% may require Rx depending on jurisdiction
Price$15–$90 / 30 ml
Full list of studies reviewed
25 studies +
  1. 1.Kapoor K, et al. Exploring Niacinamide as a Multifunctional Agent for Skin Health and Rejuvenation. Current pharmaceutical biotechnology. 2025.PMID 41088896 ↗
  2. 2.Passeron T, et al. An Investigator-Blinded, Randomized Trial of a Broad-Spectrum Sunscreen Containing Sclareolide and Niacinamide for the Prevention of Post-inflammatory Hyperpigmentation in Skin of Color. Dermatology and therapy. 2026.PMID 41240206 ↗
  3. 3.Rageh MA, et al. Egyptian National Consensus on Dermocosmetic Ingredient Selection Across Common Dermatology Scenarios: A RAND/UCLA Appropriateness Study. Dermatology and therapy. 2026.PMID 41240206 ↗
  4. 4.Breglio KF, et al. Nicotinamide for Skin Cancer Chemoprevention. JAMA dermatology. 2025.PMID 41537948 ↗
  5. 5.Allen NC, et al. Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients. The New England journal of medicine. 2023.PMID 36856616 ↗
  6. 6.Chen AC, et al. A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention. The New England journal of medicine. 2015.PMID 26488693 ↗
  7. 7.Leung AK, et al. Xeroderma pigmentosum: an updated review. Drugs in context. 2022.PMID 36856616 ↗
  8. 8.Wohlrab J, et al. Niacinamide - mechanisms of action and its topical use in dermatology. Skin pharmacology and physiology. 2014.PMID 35520754 ↗
  9. 9.Hyeraci M, et al. Systemic Photoprotection in Melanoma and Non-Melanoma Skin Cancer. Biomolecules. 2023.PMID 24993939 ↗
  10. 10.Draelos ZD, et al. International Consensus on Anti-Aging Dermocosmetics and Skin Care for Clinical Practice Using the RAND/UCLA Appropriateness Method. Journal of drugs in dermatology : JDD. 2024.PMID 37509103 ↗
  11. 11.Chen AC, et al. Nicotinamide and the skin. The Australasian journal of dermatology. 2014.PMID 24635573 ↗
  12. 12.Liu H, et al. Topical azelaic acid, salicylic acid, nicotinamide, sulphur, zinc and fruit acid (alpha-hydroxy acid) for acne. The Cochrane database of systematic reviews. 2020.PMID 32356369 ↗
  13. 13.Damian DL. Nicotinamide for skin cancer chemoprevention. The Australasian journal of dermatology. 2017.PMID 33034949 ↗
  14. 14.Tow R, et al. Recent Advances in Clinical Research for Skin Cancer Chemoprevention. Cancers. 2023.PMID 37568635 ↗
  15. 15.Surjana D, et al. Nicotinamide in dermatology and photoprotection. Skinmed. 2011.PMID 37568635 ↗
  16. 16.Draelos ZD, et al. The effect of 2% niacinamide on facial sebum production. Journal of cosmetic and laser therapy : official publication of the European Society for Laser Dermatology. 2006.PMID 22256624 ↗
  17. 17.Escudero-Góngora MM, et al. Nicotinamide: New Indications in Dermatology. Actas dermo-sifiliograficas. 2016.PMID 27377936 ↗
  18. 18.Stratigos AJ, et al. European interdisciplinary guideline on invasive squamous cell carcinoma of the skin: Part 1. epidemiology, diagnostics and prevention. European journal of cancer (Oxford, England : 1990). 2020.PMID 32113941 ↗
  19. 19.Fania L, et al. Role of Nicotinamide in Genomic Stability and Skin Cancer Chemoprevention. International journal of molecular sciences. 2019.PMID 37717283 ↗
  20. 20.Snaidr VA, et al. Nicotinamide for photoprotection and skin cancer chemoprevention: A review of efficacy and safety. Experimental dermatology. 2019.PMID 30698874 ↗
  21. 21.Singh S, et al. Interventions for bullous pemphigoid. The Cochrane database of systematic reviews. 2023.PMID 30698874 ↗
  22. 22.Hollstein MM, et al. Skin microdialysis detects distinct immunologic patterns in chronic inflammatory skin diseases. The Journal of allergy and clinical immunology. 2024.PMID 37572360 ↗
  23. 23.Chen AC, et al. Oral and systemic photoprotection. Photodermatology, photoimmunology & photomedicine. 2014.PMID 39142443 ↗
  24. 24.Tan E, et al. Nicotinamide for Skin Cancer Chemoprevention: The Jury Was Out and Still is. American journal of clinical dermatology. 2026.PMID 24313740 ↗
  25. 25.Davis MG, et al. Scalp application of antioxidants improves scalp condition and reduces hair shedding in a 24-week randomized, double-blind, placebo-controlled clinical trial. International journal of cosmetic science. 2021.PMID 41505062 ↗

Should You Try This?

15107OUT OF 10

Probably okay to try

Clinic checklist

Universal

  • Check the ingredient is listed in the first half of the INCI list to confirm meaningful concentration.
  • Look for airtight or opaque packaging -- light and air degrade active ingredients.
  • Check the expiry date before purchasing; actives degrade after opening.
  • Patch test on your inner arm for 24 hours before applying to your face.
  • Introduce one new active at a time so you can identify any reaction.
  • Store opened products away from direct sunlight and humidity.

Procedure-specific

  • Check pH as well as concentration: effective AHA exfoliation requires pH below 4; products above pH 4.5 at any concentration may not exfoliate meaningfully.
  • Start with 2 to 3 nights per week; do not use on the same night as retinol or benzoyl peroxide unless you have established tolerance.
  • Apply SPF 30+ every morning after any night of AHA use; photosensitivity is real and documented.
  • Choose your acid based on skin type: glycolic for resilient, oily, or photodamaged skin; lactic for dry or dull skin; mandelic for sensitive, acne-prone, or darker skin tones (lower risk of PIH).
  • Avoid AHAs on active eczema, rosacea flares, or freshly sunburned skin; exfoliation on compromised skin accelerates barrier damage.

Educational content only. This page summarises published clinical research and is not medical advice. Consult a qualified healthcare provider before making decisions about your care.

Researched by

Val Yermakova

Informed Girl · informedgirl.com