There is a difference between face oils and serums. Traditional serums are supplements for your skin and are water-based. A face oil serum, as the name suggests, is oil-based and is also designed to nourish the skin but operates differently to a water-based serum.
Water-based serums are skin supplements that have a smaller molecular structure than those found in oils, moisturizers and lotions and are thus able to more deeply penetrate the skin. This enables them to deposit active ingredients such as peptides, glycolic acids and/or antioxidant-rich vitamins deep in skin to produce more targeted results.
A facial oil serum has a rich, emollient character and is heavier than water-based serums. These serums contain essential oils and plant extracts that are designed to nurture and hydrate the skin and lipids which strengthen the skin barrier; they also have anti-inflammatory and antioxidant properties.