What exactly is the skin barrier?
We hear the words “skin barrier” everywhere in skincare.
Protect your skin barrier. Repair your skin barrier. Support your skin barrier.
But what actually is it?
The skin barrier isn't a separate coating sitting on top of your skin. Its main physical barrier is found in the stratum corneum, the outermost layer of the epidermis.
Research describes the stratum corneum as the skin's principal permeability and protective barrier. One of its most important jobs is limiting water loss while helping protect the body from the external environment.
Think of it as your skin's frontline defence.
What is the skin barrier made of?
A common way of explaining the stratum corneum is to imagine a brick wall.
The “bricks” are cells called corneocytes, while the material surrounding them includes an organised matrix of lipids.
Among the major lipid classes are ceramides, cholesterol and free fatty acids. Research has shown that the composition and organisation of these lipids are important to effective skin-barrier function.
Ceramides in particular play an important structural role in helping maintain the skin's permeability barrier.
But the skin barrier is more sophisticated than a simple wall. Modern research describes interconnected physical, chemical, microbiological and immunological components that work together to maintain healthy barrier function.
What happens when the skin barrier isn't functioning well?
When barrier function is disrupted, the skin may have more difficulty retaining water and protecting itself from the external environment.
One measurement researchers use to assess barrier function is transepidermal water loss, commonly abbreviated to TEWL.
TEWL describes water passing from inside the body through the epidermis and evaporating from the skin surface.
Higher TEWL can be associated with impaired barrier function, although skin-barrier health is more complex than any single measurement.
Research has linked changes in epidermal barrier function with dry, flaky and sensitive skin.
This is why skin hydration isn't only about making the surface of the skin temporarily feel softer. Supporting the barrier that helps retain that water matters too.
Why does sensitive skin need thoughtful care?
Sensitive skin is complicated.
There isn't one single explanation for why someone's skin feels sensitive, and researchers continue to investigate the biological mechanisms involved.
Scientific reviews have identified changes in epidermal barrier function among the factors associated with dry, flaky and sensitive skin.
That makes the way we care for skin important.
More products and more ingredients do not automatically mean better care.
Sometimes the better question is:
What does the skin actually need?
Where do moisturisers fit in?
Moisturisers can support the skin barrier in different ways depending on their formulation.
A scientific review describes three familiar categories of moisturising ingredients:
Occlusives help reduce water loss from the skin surface.
Humectants attract and retain water.
Emollients help smooth and fill spaces within the stratum corneum.
Research has also shown that formulation matters. Different moisturisers can have different effects on barrier function, so the word “moisturiser” alone doesn't tell us everything about how a product will behave on the skin.
Gentle skincare doesn't have to be complicated
When skin feels dry or sensitive, it can be tempting to keep adding products.
Another serum. Another cream. Another active.
But a long routine isn't automatically a better routine.
A thoughtful approach starts with understanding the role of the skin barrier and choosing products appropriate for your skin rather than simply following the latest skincare trend.
At Sanski, that philosophy is one reason we believe in keeping skincare purposeful.
Not more for the sake of more.
Just thoughtful care for skin that may need a gentler approach.
References & Further Reading
- Berardesca E, et al. (2023). Epidermal barrier function in dry, flaky and sensitive skin: A narrative review. Journal of the European Academy of Dermatology and Venereology.
View study on PubMed - Draelos ZD, et al. (2023). The Skin Barrier and Moisturization: Function, Disruption, and Mechanisms of Repair. Skin Pharmacology and Physiology.
View study on PubMed - van Smeden J, Bouwstra JA. (2023). The skin barrier: An extraordinary interface with an exceptional lipid organization. Progress in Lipid Research.
View study on PubMed - Wartewig S, Neubert RHH. (2007). Properties of ceramides and their impact on the stratum corneum structure: a review. Part 1: ceramides. Skin Pharmacology and Physiology.
View study on PubMed - Lodén M. (2012). Effect of moisturizers on epidermal barrier function. Clinics in Dermatology.
View study on PubMed