RRevelika
exfoliant

Glycolic Acid (AHA)

INCI · Glycolic Acid · also AHA, Alpha Hydroxy Acid

EWG safety

How it works

Glycolic acid is an alpha-hydroxy acid derived from sugarcane, and it has the smallest molecular size of the commonly used AHAs, which lets it penetrate the skin more readily than lactic or mandelic acid. It works by loosening the desmosomes — the protein bonds holding dead corneocytes together — accelerating their shedding and revealing smoother, more evenly toned skin underneath.

With regular use it also stimulates modest increases in dermal collagen and glycosaminoglycan content, contributing to a plumper look over time. That same small molecular size is precisely why it's more effective and more irritating than its AHA cousins — there's no free lunch with exfoliation.

The evidence

Clinical studies dating back decades have demonstrated that regular glycolic acid use improves the appearance of photodamage, fine lines, and mottled pigmentation, with effects correlating to both concentration and pH of the formulation. Longer-term use has also been associated with increased epidermal thickness and improved barrier function, contrary to the assumption that acids inherently weaken skin.

Suitability

  • Oily and combination skin: helps manage texture and dullness without added richness
  • Not ideal as a first exfoliant for sensitive or very dry skin — start with lactic or mandelic acid instead
  • Use with caution during pregnancy; low-concentration leave-on use is generally considered lower risk but data is limited
  • Dull, sun-damaged skin: one of the most effective options for improving overall radiance

Concentration

At-home leave-on products typically range from 5–10%; in-office peels can use much higher concentrations under professional supervision. I tell patients that formulation pH matters as much as the percentage on the label — a poorly buffered low-pH product will irritate even at low percentages, while a well-buffered 8% can feel gentler than a poorly made 5%.

Conflicts & combinations

  • Do not combine with retinol, salicylic acid, or benzoyl peroxide in the same routine — the combined exfoliation and irritation potential is too high for most skin
  • Always follow with broad-spectrum SPF the next morning, since AHAs increase photosensitivity
  • Pairs well with hydrating, barrier-supportive ingredients like hyaluronic acid and ceramides to offset dryness
  • Best introduced two to three nights a week before considering daily use
Suitability
Suits skin type
dry oily combo sensitive acne prone mature normal
Targets
  • uneven texture
  • dullness
  • hyperpigmentation
  • enlarged pores
Use caution with
  • redness
  • dryness
Concentration
Concentration0 – 10%
Effective from
8%
Max safe
10%
Frequently asked
What does glycolic acid do for your skin?

It exfoliates dead skin cells, improving texture, tone, and the appearance of fine lines and dullness.

Can I use glycolic acid every day?

Most people should start 2–3 times a week and build tolerance; daily use can be too irritating for many skin types.

Does glycolic acid make you more sensitive to the sun?

Yes — AHAs increase photosensitivity, so daily SPF is essential during use.

Can you use glycolic acid and retinol together?

It's generally not recommended in the same routine due to compounded irritation; alternate nights or use one AM and one PM.

Is glycolic acid safe during pregnancy?

Data is limited; many dermatologists advise using it with caution and in lower concentrations, or avoiding it and choosing lactic acid instead.

The evidence