Although Y2K beauty trends are coming back around — butterfly clips, nail art, glittery pastel shadow included  — our skin-care routines have come a long way since the early aughts. Our exfoliation routines have evolved from harsh scrubs to gentle chemical serums. Acid-based peels, particularly those formulated with glycolic acid, have gone from only being available in a dermatologist’s office to at-home options hitting the market. 

With glycolic acid appearing on more and more skin-care product labels, we figured there’s no better time to delve into the popular ingredient. Board-certified dermatologists helped us break down the basics.