When I first heard about facial oil, that is, oil that you literally apply to your face, I was shocked.
Do I actually need to put oil on my face? What if my face already has too much oil as it is?
Facial oils are typically used as emollients to soften the skin; however, these oils generally only coat the surface of the skin without forming an effective barrier.
In order to be an effective moisturizer, a substance needs to form an occlusive or semi-occlusive barrier on the skin to prevent trans-epidermal water loss (TEWL), which is water lost from the skin by evaporation into the surrounding environment.
Although facial oils may not be effective moisturizers when used alone, some of them can help to restore the skin barrier integrity and function, as well as possessing antioxidant, antimicrobial, and anti-inflammatory properties.
Structure and Function of the Skin Barrier
In order to understand the potentially beneficial applications of facial oils, we must first understand what is meant by the “skin barrier”.
The skin barrier (SB) is composed of corneocytes (keratinized skin cells) and the intercellular lamellar compartment (lipids/oils).
In the “brick wall” analogy, the corneocytes are the “bricks” that are surrounded by and held together by the intercellular lipid lamallae “mortar” to maintain the stratum corneum’s (outermost layer of the skin) integrity and its functional permeability barrier.
The stratum corneum (SC) acts as both a permeability barrier and an antimicrobial barrier of the skin.
What’s Facial Oil?
So, what exactly is facial oil–what’s in it, and should I be using it?
For the purposes of this discussion, facial oils are naturally-derived plant oils; ideally, these plant oils are extracted by cold-pressing so that their bioactive components are not exposed to heat or caustic chemicals, which could alter their composition.
Plant oils can be classified as either fixed oils or essential oils; fixed plant oils are not volatile at room temperature.
Skin lipids consist of multiple compounds, including free fatty acids (FFAs), ceramide precursors, sterols, phenols, tocopherols, and triterpenes.
Lineoleic acid is the most abundant polyunsaturated fatty acid in the skin and has a direct role in maintaining its integrity and permeability, while monounsaturated FFAs, such as oleic acid, are detrimental to the structure and function of the SB.
Phenolic compounds are antioxidants that are important for the oxidative stability of polyunsaturated fatty acids.
Triterpenes can enhance tissue repair by inducing cell proliferation and collagen deposition.