Many of you have likely heard about the skin-plumping benefits of hyaluronic acid — one stroll down the beauty aisle and you'll see the popular ingredient listed in moisturizers, serums, facial mists — you name it. The beauty industry is seemingly obsessed with hyaluronic acid, as it promises to give us moist and hydrated, baby-smooth skin — sign us up! But what exactly is hyaluronic acid and how does it work? In the kickoff episode of POPSUGAR's latest beauty explainer series, The Makeup, host, senior writer, and all-things-beauty expert Kirbie Johnson breaks down how the buzzy ingredient hydrates skin so you can decide if it belongs in your beauty routine. Watch and learn!