SERUMS + AMPOULES + OILS
Serums are likely the most well known product category as they’re quite common stateside, as well. Serums tend to be more concentrated in its active ingredients, these emollient gel-like substances often feature heavy-hitting ingredients meant to really target and treat skin issues like dark spots, wrinkles and dullness. Usually, serums are thought to have a more viscous texture then essences.
Ampoules are in the same family as essences and serums. An ampoule is a supercharged serum with higher concentrations of active ingredients that you're meant to use for a finite amount of time as a booster or when you're having a skin crisis of some sort. Chang recommends using them before your essence or serum. Ampoules usually come in smaller bottles with droppers.