You have probably heard the term “skin barrier” being used more and more recently, but what exactly is it? And how do you keep it ‘intact’? Let's dive into it!

What is a skin barrier & why is it important?

The skin barrier generally refers to the outermost layer of skin called the stratum corneum. The skin is the first line of defense for the body against infection, dehydration, pollution, microbes, and other external aggressors, and the stratum corneum is the first blockade of this protection. It prevents the deeper layers of skin from drying out, and also gives the skin its acidic pH. The stratum corneum is the top of 5 layers in the epidermis, and consists mainly of dead skin cells called corneocytes. 

These dead skin cells are surrounded by intercellular lipids which act as a cement to keep the cells in a brick and mortar structure. These lipids are composed of fatty acids, cholesterol, and ceramides. When the cells are not tightly packed with lipids, more water can escape from your skin, and more harmful aggressors can enter.

What happens when you have a damaged skin barrier?

When the barrier is disrupted, your skin will be less effective at retaining moisture and protecting the deeper layers. The skin has its own methods of self-repair, but continuous barrier disruption can overpower these mechanisms. This may cause increased water loss, decreased skin elasticity, and decreased skin firmness. 

The skin barrier also contains the skin’s natural moisturizer, fittingly called the Natural Moisturizing Factor (NMF). The NMF helps to retain water and supports the barrier function. Amino acids are a key component of the NMF, especially serine, threonine, alanine, and pyroglutamic acid. 

You may have also heard of the skin’s microbiome. A microbiome is simply a collection of all microbes that naturally live on our skin and in our bodies. The skin’s microbiome is directly linked to the skin barrier and plays a role in keeping the skin healthy. In a sense, it is similar to the immune system of the skin barrier! There are both good (commensal) and bad (pathogenic) bacteria on our skin naturally, and keeping them balanced leads to healthy skin and an effective skin barrier. 

Important things to consider to protect your skin and keep your barrier intact:

• Use products with a pH that is similar to that of the skin
• Avoid using harsh organic solvents in your products
• Always protect your skin from UV exposure with sunscreen
• Use products with a variety of humectants, emollients, and occlusives 
• Use products that contain ingredients that help support the skin’s lipids or NMF, such as Three Ships Beauty’s new Replenish Barrier Repair Serum

Overall, the skin barrier is a product of all of the above components and more. Corneocytes, intercellular lipids, NMF, the acid mantle, and the microbiome all contribute to a healthy skin barrier.