A decade ago, the standard advice for dull or congested skin was to scrub harder. Today the shelf looks different. Glycolic, lactic, salicylic, and mandelic acids now sit in the routines of people who would never have described themselves as peel users. That shift happened for good reasons, and it created a new set of problems. Acids work by loosening the bonds that hold dead skin cells together, which means frequency, concentration, and pairing matter far more than most labels admit. If you want the background on how a single acid toner became a fixture in cities like New York, check this guide. What follows is the practical version: what each acid actually does, who it suits, and how to use it without wrecking your skin barrier.
