What Is Glycolic Acid? We Asked a Skin-Care Expert to Explain

If you haven't yet met glycolic acid, prepare to fall in love at first swatch. This skin-care acid falls into the category of "alpha hydroxy acids," or AHAs, which are naturally derived acids typically found in sugarcane, sugar beets, and fruit. Because a molecule of glycolic acid is smaller than its AHA counterparts (including lactic, mandelic, and citric acids), its particles are better able to penetrate the skin and are considered to be more effective.

"Glycolic acids are often used to treat acne scarring, skin discoloration, and signs of aging such as fine lines and wrinkles," Anita Sun, a medical esthetician and the founder of Dermovia, told POPSUGAR. "It is also effective in treating skin conditions such as psoriasis, melasma, seborrheic keratosis, and keratosis pilaris." In other words, it's really, really ridiculously good at resurfacing the skin. But that's not all.

Sun added: "Glycolic acid helps to boost collagen production and is effective in plumping the skin, supporting healthy skin tissue to remain firm and prevents wrinkles from forming. It's also effective in removing surface dead skin cells and removing oil build up in pores."

By incorporating this ingredient into your skin-care routine, you'll notice a brighter and more even complexion — sometimes in as little as 24 hours.