Ingredients

Lactic Acid

Written by Reviewed by the SYNC editorial team Published Last reviewed Editorial standards

Lactic Acid — an alpha hydroxy acid, originally derived from milk and now usually made synthetically, that exfoliates the skin while also helping it hold onto moisture. Its larger molecular size makes it gentler and slower to penetrate than glycolic acid, so it is often chosen for sensitive or drier skin. Beyond exfoliation, it is a natural component of the skin's own moisturizing factor.

Key points

  • Lactic acid is a water-soluble AHA with a larger molecule than glycolic acid, which generally makes it milder.
  • In addition to loosening dead surface cells, it has humectant properties that support skin hydration.
  • It is commonly used to improve texture, smoothness, and radiance, especially in drier or more reactive skin.
  • It is a naturally occurring part of the skin's natural moisturizing factor (NMF).
  • Like other exfoliating acids, it can increase sun sensitivity, so daily sunscreen is advised.

Frequently asked

Is lactic acid suitable for dry skin?

Yes, its humectant qualities make it a popular choice for dry skin because it exfoliates while helping the skin retain moisture. Pairing it with a good moisturizer can further reduce any dryness.

Is lactic acid vegan?

Although it was traditionally sourced from milk, most modern cosmetic lactic acid is produced through fermentation of plant sugars or made synthetically. Check the specific product if a fully vegan formula is important to you.

Related topics

This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.

Encyclopedia

Further reading

This entry was written and checked against the sources below. They are published by clinical and scientific bodies, they are listed most readable first, and each one opens in a new tab. They are background for the whole entry rather than footnotes to individual sentences.

  1. Alpha hydroxy acid facial treatments DermNet NZ Clinical guidance dermnetnz.org
  2. Ammonium Lactate Topical: MedlinePlus Drug Information MedlinePlus Clinical guidance medlineplus.gov
  3. Cosmetics Alpha Hydroxy Acids U.S. FDA Regulatory and safety fda.gov
  4. Effects of alpha-hydroxy acids on the human skin of Japanese subjects: the rationale for chemical peeling PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov
  5. Chemical peels (face peels) DermNet NZ Clinical guidance dermnetnz.org
  6. Guidance for Industry: Labeling for Cosmetics Containing Alpha Hydroxy Acids U.S. FDA Regulatory and safety fda.gov

SYNC does not publish medical advice. Nothing here replaces a consultation with a doctor or a pharmacist about your own skin.