Another major player co-opted from K-beauty are ampoules — super concentrated serums that generally deliver a higher potency of skin nourishing ingredients. “Ampoules have been a part of Korean skincare for a very long time,” says Soko Glam co-founder and esthetician Charlotte Cho . “They don’t contain fillers like emulsifiers or emollients that cleansers and moisturizers do, so the active ingredients make a big difference in your skin.” Many are made to target specific issues (like dark spots, the effects of aging, or dry skin) and the most hardcore of skin-care fanatics mix and match them depending on their skin’s particular needs of the day. Others — primarily those made by American-based brands — are built for multitasking because that’s how our culture likes to roll.