WHAT IS SKIN BARRIER FUNCTION?

The role of the skin is to function as the first line of defence from the external environment, keeping irritants out and moisture in. The cells in a healthy skin barrier are tightly packed and organised, protecting you from allergens, UV rays and microorganisms. Simultaneously, it behaves as a moisture barrier (also known as an epidermal permeability barrier), keeping your skin hydrated by preventing moisture evaporating through a natural process known as transepidermal water loss (TEWL).

The skin is an intelligent interface consisting of three main layers; the epidermis, dermis and hypodermis, of which all comprise of even more sub-layers. The stratum corneum is where most people focus when they refer to the skin as a barrier, because it’s the outermost layer of skin within your epidermis. The composite material which makes up the architecture of this top layer is viewed to have a brick and mortar structure. It contains dead skin cells, known as corneocytes (the bricks), surrounded by an intracellular lipid matrix (the mortar). The stratum corneum lipids within this matrix include; 50% ceramides, 25% cholesterol, and 15% free fatty acids (1). However, your skin is a little more complex than just the top layer, so let’s take a closer look.

SKIN STRUCTURE AT THE CELLULAR LEVEL

It’s important to remember that the biological structure of each skin cell (when alive) doesn’t resemble a hard, static brick and instead, is more similar to a washing detergent pod - a flexible pocket filled with water and other biological components. To ensure your skin stays hydrated by keeping water in, each cell is surrounded by a flexible wall (the film of the washing pod), which is made up of lipids (known as the phospholipid bilayer), such as ceramides, cholesterol, fatty acids and crucially, essential fatty acids. But what is the function of a lipid? These components are all absolutely necessary for healthy skin barrier function. All of them, except essential fatty acids, are naturally produced by your body to form a lipid barrier, therefore it is important to incorporate skincare products that are rich in essential fatty acids into your routine.

YOUR SKIN'S RENEWAL PROCESS

Your skin naturally renews itself approximately every 28 days, although this can slow down with age (2). During this replenishment process each skin cell (keratinocyte) travels from the bottom skin layer where it was created, upwards to the outermost layer of the epidermis, in a process known in dermatology as keratinization. During this biological process, each skin cell changes its shape slightly in order to sit a little more comfortably within the next skin layer, however when your skin cells reach the uppermost layer of your epidermis (the stratum corneum) they become dead cells (corneocytes). Here your dead skin cells begin to undergo desquamation, where each skin cell detaches from one another and eventually comes away from your skin surface (3). Exfoliating helps to speed up desquamation and skin cell turnover by removing sets of dull and dead skin, so that newer skin cells can be brought to the surface. That's why exfoliated skin looks brighter and more radiant. In terms of keeping your skin barrier healthy, it’s important that each individual skin cell within each layer is healthy. If your skin cells are healthy at the beginning of the skin’s natural renewal process, then as they travel upwards towards your skin surface to fulfil their service, your barrier will be strong and healthy from top to bottom.

SKIN BARRIER DAMAGE

When your skin barrier is damaged some of your skin’s key building blocks are missing, which means that your skin structure is cracked and disorganised. At the cellular level, the skin cell wall may be partially damaged, lacking lipids, such as essential fatty acids. This allows irritants and allergens to penetrate your skin more easily, which can trigger inflammation, breakouts, sensitivity, allergy symptoms and peeling skin. The gaps lead to increased loss of water vapor (TEWL), resulting in dehydrated skin (oily skin can be dehydrated too, not just dry skin) (4). In addition to an impaired epidermal barrier, your natural skin renewal process will also slow down, causing a buildup of dead skin cells on your skin’s surface, which visibly appear rough and dull. 

WHAT CAUSES SKIN BARRIER DAMAGE? 

• Harsh, alkaline (low pH) cleansers rich in sodium lauryl sulphate (SLS) may be good at removing stubborn makeup, but can strip your skin of its natural oils and lipids.
• Over exfoliating via physical or chemical exfoliation (e.g. alpha hydroxy acids) can cause irritation and damage. Although your beauty routine may benefit from chemical exfoliants, overuse has its downsides.
• Overdoing it with the actives. Retinol, glycolic acid and benzoyl peroxide, to name a few, work great when used correctly, however high concentrations such as those in chemical peels can have strong side effects.
• External irritants, such as the sun’s UV rays, environmental pollution from the air around you, fragranced essential oils and harsh hair removal methods can damage your skin barrier, triggering inflammation.
• Genetic mutations in the filaggrin gene, are common in patients with medical skin disorders associated with barrier abnormality e.g. atopic dermatitis/atopic eczema.

HOW TO REPAIR A DAMAGED SKIN BARRIER

STEP 1 - PREVENT DAMAGE

Whether you’ve over exfoliated or mixed too many actives at once, stop any further damage to your skin barrier by simplifying your skincare routine and going back to basics. Stop exfoliating and only use a gentle cleanser, moisturiser/facial oil and sunscreen (in your AM routine), that contain pure and ‘skin-native’ ingredients - those which naturally exist within your skin and suit sensitive skin types, such as linoleic acid and hyaluronic acid. Also avoid heavily fragranced skin care products to allow for skin recovery. If you have acne prone skin and are using strong active treatments, that have side effects such as skin peeling, try applying your moisturising cream first to function as a buffer. Alternatively try using more gentle actives, for example switch your glycolic acid toner for a lactic acid skin care product.

STEP 2 - REPAIR SKIN

So you’ve stopped inflicting more damage, but now you're searching for ways to repair your skin. Much like how amino acids are the building blocks of muscle; fatty acids, and especially essential fatty acids, are the building blocks of skin cells. Remember, your body can’t make essential fatty acids by itself, so these need to be supplemented. A plant oil rich in essential fatty acids, such as Nêô Sephiri’s Kalahari Melon Oil has 70% linoleic acid (an omega-6 essential fatty acid), which will directly repair your skin barrier. Linoleic acid also helps to make ceramides, crucial lipid components of your skin, which are lost when your barrier is impaired. Products rich in linoleic acid and ceramides directly replenish your natural stores and strengthen your skin cell wall. In fact, science shows using a mixture of ceramides, fatty acids and cholesterol in a 3:1:1 ratio accelerates skin barrier repair (5). 

STEP 3 - PROTECT 

There isn’t any point in building a wall just to knock it back down again, be patient and gradually incorporate actives back into your routine, using them once a week to begin with. Ensure you take full account and personal care in supporting and maintaining your skin barrier all year round, by investing in a face oil rich in skin repairing ingredients. Our Kalahari Melon Oil gifts your skin with the essential fatty acids and antioxidants it needs to stay healthy, whilst also forming a protective occlusive layer that reduces TEWL and improves skin hydration.

 

To learn more about Kalahari Melon Oil visit our journal or contact us via our email address: info@neosephiri.com