Emollients are the backbone to most cosmetic skincare formulations. They’re not what we typically think of when we hear “skincare actives”, but you’d be surprised just how important they are and what benefits they can provide.
Skincare formulations containing emollients vary from lotions, creams, balms and pastes – the content of emollients can dictate the product type and function (for example, oil in water preparations are typically around 20% emollients). Whilst doing your skincare routine, you are bound to come across a multitude of skincare emollients, benefits of which you may or may not be aware of.
In this article we dive into the types of emollients, their mechanism of action and assortment of benefits.
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What are Emollients?
Emollients are any agents which persist on the surface of the skin until rubbed-off or rinsed-off. They are most commonly oil-based and are not designed to penetrate the stratum corneum (the outer most layer of the skin). Unlike other cosmetic ingredients, where skin penetration is key, emollients actually work better when they are firmly affixed to the surface of the skin.
If you can feel a product on your skin many minutes after application, the chances are you are feeling emollients sitting on the surface of your skin. The higher the emollient content, the ‘heavier’ a product may feel on your skin. That’s why we find emollients most commonly in night creams, balms and pastes, when the sensory characteristics of a product are less important to consumers.
types of emollients
The emollient group features a wide spread of ingredients (yes, pun intended). The largest categories feature synthetic and natural emollients, which can be broken down into oil-based and wax-based emollients.
Table 1: Emollients categorised via type (synthetic/Natural & Oil/Waxes)
Synthetic Oil | Synthetic Wax | Natural Oil | Natural Wax |
Dimethicone | Cera Microcristallina | Jojoba Oil | Candelilla Wax |
Paraffinum Liquidum | Paraffin Wax | Rosehip Oil | Bees wax |
Isododecane | Montan Wax | Coconut Oil | Ozokerite |
Hydrogenated Polyisobutene | Synthetic Wax | Argan Oil | Carnauba Wax |
Emollient Mechanism of Action
Emollients have a high molecular weight and viscosity. This means that when applied topically, they serve as an additional barrier to the skin.
The skin’s natural barrier function is responsible for keeping the inside in, and the outside out. This includes microorganisms, lipids and water. Very few molecules can pass through the epidermis, but one of the molecules that can pass through, is water (H2O). When water moves from the dermis through the epidermis and into the atmosphere, we call that trans-epidermal water loss (also known as TEWL).
When emollients are applied to the skin, they act as an additional barrier for the water to pass through to reach the surrounding atmosphere. The high molecular weight of these emollients makes it difficult for water molecules to navigate through. Additionally, emollients are oil-based, and as we know, water and oil do not mix easily, making it challenging for the water from inside the skin to transpire.
Our skin is in constant homeostasis with its environment. If the external environment is dry, the concentration gradient of water from inside of our skin to the outside atmosphere is greater, therefore, our skin transpires more. In a humid environment, the water concentration gradient is reduced, therefore, trans-epidermal water loss (the movement of water from inside to the outside of the skin) is also reduced. The addition of an emollient on the surface of the skin creates a hyper-humid environment. This reduces the concentration gradient of water from inside the skin to the outside atmosphere to practically zero, which reduces trans-epidermal water loss.
What are the benefits of Emollients?
Improvement in Skin Hydration
As described above, emollients reduce trans-epidermal water loss, leaving more water within the dermis (viable layer of the skin), making your skin feel more hydrated. This is especially important for people with extremely dry skin or an impaired skin barrier. When the natural skin barrier is damaged (potentially due to conditions such as eczema or psoriasis), emollients can step-in to act as the skin barrier.
Improves the appearance of fine lines & Skin Texture.
The surplus of water in the dermis acts as a ‘filler effect’. The water is stuck within the dermis and accumulates, slightly expanding the dermis. The added volume within the dermis applies tension on the epidermis (outer layer of the skin), which can give a temporary effect of reduction in the appearance of fine lines.
Non-sensitising
Emollients are non-sensitising ingredients. They are sometimes referred to as ‘non-active ingredients’ because they do not elicit any changes in the physiology of the skin. They simply act as an additional barrier for the skin. Please beware that using emollients on open-wounds is not recommended.
what are the drawbacks of emollients?
Emollients are quite commonly known for their sensory characteristics, they’re pretty much unavoidable when it comes to applying a barrier on your skin which is designed to last. love it or hate it, emollients typically feel heavy on the skin.
With excessive emollient use, your skin may tend to sweat a little more too, but those effects are temporary and can be resolved by simply removing the emollient. The major drawback of emollients is that they are (in the majority of cases) comedogenic, also known as, pore-clogging.
On this illustration, a pilosebaceous unit is depicted. Sebum (an oil) is produced in the sebaceous gland and travels up the hair duct. If a heavy emollient is covering the pore (opening to the pilosebaceous unit), the sebum may not be able to escape, leading it to pool around the hair shaft. Unfortunately, the sebaceous gland is unaware that the sebum isn’t being expressed on the surface of the skin, and keeps on producing sebum.
The build up of sebum beneath the surface of the skin attracts pathogens to the site (including Cutibacterium Acnes). The build up of bacteria results in an immune response from white blood cells, this leads to an inflammatory response (typically associated with acne).
The removal of emollients from the surface of the skin will not immediately clear the skin up. Acne can persist on the skin for up to 28 days. People with acne-prone skin tend to avoid highly emollient based products for this reason.
