With innovative skin-care products and cosmetics like BB creams, sheet masks , and cushion compacts , it’s no wonder we’re obsessed with all things Korean beauty. But, as more and more new products and formulas are introduced into the Western world , things can get a bit blurry. Case in point: the difference between serums, ampoules, emulsions and essences. If you have no clue what an emulsion or an ampoule even is and are still not sure whether or not you need a serum or an essence, keep reading. We help to clear things up, below. WHAT IS A SERUM? In most skin-care routines, serum is the step after cleansing, but before moisturizing. And, while these lightweight, concentrated formulas have consistency in common, the benefits vary. From serums formulated with antioxidants to layer under your sunscreen during the day to anti-aging serums to press into your skin before bedtime, serums may have a lightweight texture, but when it comes to skin care b...