Essences, serums and ampoules are usually water-based skin treatments with thinner texture and fluid consistency than facial oils, making them suitable for morning and night time skincare routines. Serums are generally thicker and more concentrated than essences, while ampoules are more concentrated than serums.
Facial oils (yes, you guessed it right!) are oil-based treatments designed to target specific skin concerns. Since facial oils have a rich and emollient texture that's typically heavier than water-based serums, adding a few drops into your night time skincare routine is the way to go.