Lactic Acid: what it is in skincare

An AHA that at low levels hydrates and at higher levels helps gently smooth and renew the skin surface.

What it does

Function: exfoliant (AHA) / humectant. Humectants draw water into the upper layers of skin, the backbone of K-beauty "dewy" hydration. They work best sandwiched under an emollient or occlusive that locks the water in.

How to spot it on a label

On a Korean product's INCI list, look for Lactic Acid. Ingredients are listed high-to-low by amount, so its position hints at how much is in the formula. See all humectants →

✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed 2026-06-21.

General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.