What your skin barrier is and why it’s so important

What is a skin barrier Elizabeth Olsen

We suss out why it’s such a big deal

Beauty Crew Beauty Writer / October 15 2019

Whether you’re a skin care fanatic or a bit of a novice, chances are you’ve heard the about the importance of your skin barrier (seriously, they talk about it in, like, every skin care product commercial). And while many of us know a healthy skin barrier will give you good skin, the thing is, most of us don’t even know what a skin barrier actually is to begin with.

So, we’re probably doing a really terrible job of keeping it in good nick, huh? To suss out what a skin barrier is and what we’re supposed to be doing to keep our skin looking as healthy as possible, we spoke to PhD scientist, skin coach and founder of Qr8, Dr Michele Squire.

What is a skin barrier?  

What do you think of when you picture your skin barrier? Anyone else think of a little wall on your skin, trying to hold in a whole heap of water dispersed from our glorious skin care products? Well, you’re not far off. However, the science-y explanation is a little more specific.

“We often think of the ‘skin barrier’ as simply being a static protective layer that keeps us waterproof (like cling wrap),” says Dr Squire. “In reality, it is a complex defence mechanism that not only regulates excessive trans-epidermal water loss (TEWL) and traps water for skin hydration, but defends us against microbial, physical, UV and free radical damage, selectively absorbs or repels chemicals we apply to it, senses the environment, linking it to the body’s immune and nervous systems - all whilst continuously shedding old skin cells and renewing itself!”

Um, we feel like we need to sit down after reading that! Who knew our little ol’ skin barrier did so much? “These functions are all linked in an elaborate dance involving multiple cell types, chemicals, nerves and microbes,” adds Dr Squire.

In a nutshell, not only does your skin barrier keep the good stuff in (moisture), but it keeps the bad stuff out (harsh environmental factors, irritants and the like). The top layer of your skin is called the stratum corneum (SC), and Dr Squire says this is the first line of defence.

“The SC consists of layers of waterproofed skin cells (corneocytes) that are packed into dense sheets and embedded into a highly organised pattern of lipids (ceramides, cholesterol and free fatty acids). This structure is often compared to a brick wall - the corneocytes are the bricks and the mortar is the lipids that sit between the cells,” explains Dr Squire. 

“Helping to regulate skin hydration is also a group of water soluble substances (like glycerol, sodium PCA and urea, along with amino acids) contained inside the corneocytes. Collectively, these are called Natural Moisturizing Factor (NMF) and its function is to absorb and hold water, keeping your outer skin layers hydrated. Being water soluble, NMF can easily be washed away from the SC, but your barrier lipids perform double duty, helping to seal NMF into the corneocytes.”

How do you know if your skin barrier is healthy?

Well, it’s actually pretty simple. All you have to do is pay attention to your skin – if it’s rough, dull, flaky or inflamed, you’ve got some repairing to do. “In healthy skin, your barrier does excellent protective duty, especially considering the insults it is exposed to daily – UV, temperature extremes, mechanical stress, infectious agents and pollution,” says Dr Squire. 

“Without enough water, your SC dehydrates and develops cracks, leading to the characteristic dry, red, irritated, reactive, scaly, acutely sensitive skin we associate with barrier damage. Barrier issues are especially problematic in older skin as SC lipid production decreases with age.” 

While not drinking enough water, drinking too much caffeine and alcohol, or the joys of ageing skin may be to blame, Dr Squire says a damaged skin barrier could also mean the ingredients you’re using in your skin care routine are too harsh for your skin. “We often don’t consider the injury we expose our skin to daily simply by performing our skin care routine! Some chemicals and skin care techniques have the potential to disrupt the finely organised architecture of the SC, leading to loss of the skin’s water holding capacity.” 

How to keep your skin barrier healthy

“Anyone who has experienced skin barrier issues knows that prevention is better than cure! It can take your skin barrier months to return to normal after being damaged,” says Dr Squire.

If you want to avoid months of mending, Dr Squire recommends maintaining your skin barrier by preventing excess water loss and keeping your SC intact. “The majority of my new clients complain of dry or sensitive skin, but often moderating their use of products/techniques that remove SC lipids or corneocytes (soaps, chemical and physical exfoliants, cleansing brushes/devices/cloths, and some cleansers) resolves sensitivity issues completely,” she says. 

Along with minimising products and techniques that rob your skin of lipids, it’ll come as no surprise that moisturising is pretty crucial. “Topical application of moisturisers that mimic components of the SC and NMF, and also contain occlusive ingredients, have been shown to improve the skin barrier in experimental models of skin dryness,” says Dr Squire. 

Get your shopping list out, here’s what ingredients Dr Squire says to look out for: “Look for products with skin identical lipids (ceramides, cholesterol, fatty acids), humectants (amino acids, glycerine, urea, sodium PCA, sodium lactate, hyaluronic acid) and occlusive agents (silicones, petrolatum, mineral oil, waxes) to protect your skin barrier and relieve dry skin if the damage is already done.”

How do you repair a damaged skin barrier?

If you’ve really screwed up and you’re suffering dry skin symptoms such as itchy skin, flakiness and roughness, Dr Squire recommends staying hydrated from the inside out - which means drinking lots of water – as well as using fragrance-free skin care (emollients are your friend!). “If you’re experiencing weakened barrier function, I recommend a simple routine of cleansing with a mild, non-fragranced cleanser, moisturising (look for the ingredients I outlined above) and sunscreen - the La Roche-Posay Toleriane and Avène Tolerance ranges are ideal.” 

La Roche Posay Toleriane Sensitive

Avène Tolérance Extreme Cream

“Sometimes you will have to forego cleansing entirely as even water can irritate those with a compromised skin barrier,” says Dr Squire. “And a word of warning: Skin barrier issues take time to resolve (even longer if you are older) so you may have to stick to this routine for some time.”

In terms of what to avoid, just stay away from anything that might irritate your skin further like harsh soaps, exfoliants, vitamin A, and fragranced skin care. It’s also a good idea to stay away from really hot water when showering. “Because the physical barrier of the SC has been disrupted, potentially irritating ingredients can penetrate deeper into the skin, aggravating existing barrier issues.”

A moisture barrier can be tricky to repair with home care/home remedies if there is an underlying medical condition, skin condition (like atopic dermatitis) or severe skin damage. If you have chronically dry, scaly, thickened skin, you should seek the help of a GP or dermatologist for medical advice.

Looking for more tips on how to tackle severe dry skin? We asked three skin experts to talk us through the causes of dry skin and their recommendations for the best over-the-counter products

What is your go-to moisturiser for smooth, hydrated skin? Share with us in the comment section below.

Main image credit: Getty

Erin Docherty is a Beauty Writer for BEAUTYcrew and a Grooming Writer for Men's Health magazine. She has a keen interest in cosmeceutical skin care and is currently working on minimising her 9-step skin care routine – because ain’t nobody got time for that. When she’s not writing about the latest beauty news, or applying copious amounts of serum, you can find her spending all her money in Sephora.