Glycolic Acid



Glycolic Acid at a glance

  • The most-researched AHA (alpha hydroxy acid) with a long history of safe use
  • Helps renew skin’s surface, visibly improving several signs of ageing
  • Significantly increases skin’s hydration
  • New research shows it may protect skin from UV damage

Glycolic Acid description

Glycolic acid is a type of alpha hydroxy acid (AHA) that, like other ingredients in the category, can act as a water-binding agent and, when properly formulated and used in concentrations of 5% or greater, as an exfoliant. While there are several other types of AHA, glycolic acid is by far the one with the most research backing its effectiveness. In its capacity as an exfoliant, it can help shed dead skin to renew skin’s surface, which results in the improvement of several signs of ageing, including sun damage, uneven tone, rough, flaky patches of skin, fine lines, and wrinkles. These benefits are obtainable by choosing a leave-on AHA exfoliant that contains 5–10% glycolic acid when it is used as the sole exfoliating acid. It must also be formulated at a pH between 3-4, which is where optimal exfoliation occurs. Studies also show that glycolic acid significantly increases skin’s hydration. It does this by helping skin make substances like mucopolysaccharides, which aid hydration by increasing skin’s natural content of hyaluronic acid, which in turn enhances resilience and improves texture. One exciting new note about glycolic acid: emerging research shows it might even protect skin against UV damage (in addition to reducing its damaging after-effects), though more studies need to be done (and of course it doesn’t replace the need for sunscreen). It’s worth noting that most AHA products do carry a warning about unprotected sun exposure, since the manner in which AHAs exfoliate reveals fresh new skin that can be more susceptible to sun damage. Glycolic acid occurs naturally in sugar cane, but is most effective when synthesised in a lab, where its potency and concentration are optimized for use in skin care. Using plant sugars, like sugar maple, for their glycolic acid content is an option, but the bulk of the reimized for effectiveness, purity, stability, and pH, all critical to getting effective glycolic acid products.

Glycolic Acid references

  • Molecules, April 2018, 23(4), ePublication
  • DNA Cell Biology, February 2017, pages 177-187
  • Journal of Clinical and Aesthetic Dermatology, October 2015, pages 21-26
  • BioMed Research International, 2015, Volume 2015
  • Dermatology Research and Practice, February 2015, Volume 2015

Peer-reviewed, substantiated scientific research is used to assess ingredients in this dictionary. Regulations regarding constraints, permitted concentration levels and availability vary by country and region.

Ingredient ratings


Proven and supported by independent studies. Outstanding active ingredient for most skin types or concerns.


Necessary to improve a formula's texture, stability, or penetration.


Generally non-irritating but may have aesthetic, stability, or other issues that limit its usefulness.


There is a likelihood of irritation. Risk increases when combined with other problematic ingredients.


May cause irritation, inflammation, dryness, etc. May offer benefit in some capability but overall, proven to do more harm than good.


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Not rated

We have not yet rated this ingredient because we have not had a chance to review the research on it.