Your ‘skin barrier’ protects your skin and keeps it hydrated – here’s how to look after it

By Daniel Sebastia-Saez, Lecturer of Chemical Engineering, University of Surrey; Daniela Carta, Lecturer in Physical Chemistry, University of Surrey; and Lian Liu, Reader, School of Chemistry and Chemical Engineering, University of Surrey

London, Nov 9 (The Conversation) Skincare is a hot topic on social media. There’s a seemingly endless number of posts and videos talking about which skincare products consumers should use (or avoid) if they want good looking, youthful and healthy skin.

But some of the information being presented online may be unintentionally misleading – and could put you at risk of inadvertently damaging your skin rather than making it look healthier.

While our skin is a powerful barrier that prevents many harmful foreign substances from entering our body, the use of a cocktail of the wrong skincare products could damage your “skin barrier”.

What is the skin barrier?

The outermost layer of the skin, the stratum corneum, constitutes the actual skin barrier. It’s comprised of dead cells made of keratin – the same protein of which nails and hair are made.

The way the keratin cells are laid out is reminiscent of a bricks-and-mortar wall. The mortar between the keratin bricks is made by layers of lipids (fats) – such as ceramides, cholesterol and fatty acids. This layout makes it difficult for any potentially harmful molecules to get past the skin barrier and into the body.

The skin barrier acts as the first line of defence against environmental aggressors – preventing pathogens, allergens, chemicals and harmful microorganisms from getting into our body. The skin barrier also regulates body temperature, and keeps the skin hydrated by preventing water loss. This prevents dryness and flakiness – essential for a smooth, healthy complexion.

What damages the skin barrier?

If the skin barrier becomes damaged in any way, it will be less able to maintain hydration. This leads to water loss and the skin becoming more vulnerable to external aggressors – making it easier for harmful substances to enter the barrier and damage the skin cells . This subsequently leads to the skin looking dull, being less flexible and losing its glow and suppleness.

When this happens, it’s known as an “impaired barrier”. Lifestyle choices – such as unbalanced diet, smoking, stress, excess and unprotected sunlight exposure and lack of sleep, to include only a few – can affect the healthy state of our skin barrier.

Several substances found in commercial skincare and cosmetic products can also unwittingly contribute to damage the skin barrier. Harsh products such as alcohol-based sanitisers, detergents and exfoliants can pull out the epidermal barrier covering our skin if used in excess.

Excessive use of physical exfoliants (such as face scrubs) can have the effect of sanding down the bricks-and-mortar structure of the skin barrier.

In the case of potential damage from chemical exfoliants, however, the mechanisms are more complex.

AHA (alpha-hydroxy acids) exfoliants like glycolic, lactic and citric acids, work by dissolving the lipid mortar – allowing these products to remove excess dead keratin cells. On the other hand, BHA (beta-hydroxy acids) exfoliants enter our pores and remove excess oil and sebum. This is why these products are effective on acne. But when used in excess or when combined with the wrong products, some exfoliants could increase skin sensitivity. This is why it’s recommended you only use products suited for your specific skin type.

It’s also worth noting that teenagers may be particularly at risk of damage to their skin barrier if they aren’t careful. Hormonal changes cause excessive sebum production and inflammation in the skin. This gives rise to increased reactivity to harsh ingredients and sunlight. It’s important young people don’t use harsh products excessively.

Can you repair the skin barrier?

The good news is that the skin barrier can often repair itself after damage occurs – often within a couple of days if the harm is superficial. It can take several weeks in the case of healing wounds, however. The repair process involves the regeneration of new skin cells and the replenishment of the lipid matrix essential for the barrier’s function.

Generally speaking, skin barrier function can greatly benefit from the use of gentle products, such as mild cleansers and moisturisers (particularly those that contain ceramides).

A healthy diet and keeping hydrated can also support skin health from the inside out – providing nutrients essential for skin regeneration. Research has even found a link between the health of the skin barrier and the gut microbiome. As such, foods containing fatty acids, prebiotics and probiotics may have a beneficial effect on the skin barrier by promoting the health of the gut microbiome.

Wearing sunscreen daily also protects the skin barrier from UV damage which will further prevent degradation of the skin barrier and support recovery.

The skin barrier is quite resilient and can put up with a lot. Protecting and nurturing this barrier by avoiding harsh products in your skincare routine, and by following a healthy diet and keeping hydrated, you will give your skin the best chances of staying healthy and functioning as it should. (The Conversation) SCY