Published in Spa + Clinic. Issue 101 June 18th, 2025
Dehydrated skin has become increasingly prevalent in clinical practice. Skin professionals frequently observe symptoms such as sensitivity, angiogenesis and redness— indicators of low-grade inflammation. This phenomenon, now referred to as skinflammation, is most often the result of an impaired or weakened skin barrier.
The core components of maintaining skin health and integrity.
The skin’s barrier is made up of four key components, each playing an important role in keeping our skin healthy and protected. First, there’s the physical barrier, which is made up of corneocytes — tough little cells arranged like bricks in a wall. They’re strong and sturdy, acting as our skin’s first line of defence against physical damage. Then there’s the chemical barrier, which you might know as the acid mantle (though these days it’s more commonly called the hydro-lipidic barrier). This layer includes sebum, sweat, and natural moisturising factors (NMFs). Sebum is produced by our sebaceous glands and is made up of things like fatty acids and cholesterol, while sweat comes from our sweat glands and contains salts, waste, and moisture-attracting compounds — the NMFs — that help keep our skin hydrated. The microbiome barrier is another important player. It lives right on the surface of our skin, nestled in the hydro-lipidic layer, and extends a few layers into the stratum corneum. Below that? The skin is completely sterile. Finally, there’s the immune barrier, where immune cells called Langerhans cells keep watch for harmful bacteria or foreign substances. When they sense trouble, they kick off an immune response — often showing up as redness or inflammation. Together, these four barriers work in harmony to protect, balance, and support the skin. Among these, the chemical barrier plays a key role in regulating moisture loss from the stratum corneum. When functioning optimally, the skin loses approximately 500–600 ml of water daily through insensible perspiration. This water loss is tightly regulated by the hydrolipidic barrier, which is highly responsive to changes in Trans-Epidermal Water Loss (TEWL). Even a 1% increase in TEWL can prompt the body to increase sebum production — an immediate defence mechanism designed to reinforce the barrier and prevent further moisture loss.
Why does the skin react so quickly?
Skin dehydration doesn’t happen all at once — it’s a gradual process that unfolds in stages, often going unnoticed until symptoms become
more visible or uncomfortable. It typically begins with mild dehydration, which might not be obvious to the client but can be easily picked up by a trained skin professional. As the skin loses moisture, the next stage is tightness — that dry, tugging sensation we often feel. This happens because the corneocytes (our skin’s outer cells) start to shrink, and tiny, invisible tears can form in the epidermis. These micro-tears make it easier for irritants and allergens to penetrate, worsening water loss and barrier damage. If the skin continues to lose moisture, it can begin to feel rough or uneven. At this point, the corneocytes are so dehydrated that some of them begin to break apart. Though we can’t see it, we can feel it — this is the stage where rough texture becomes noticeable. The most severe stage is known as xerosis. This is when the skin barrier has essentially broken down. The corneocytes have shrunk significantly and in large numbers, leading to visible cracks, flaking, and irritation. It’s a clear sign that the skin is in distress and in need of serious hydration and barrier repair.
The Link Between Barrier Function and Skin Health
When the skin’s hydrolipidic barrier is healthy, the physical and microbiome barriers also function well. Sebum is balanced, the complexion appears even, and blemishes are minimal. In short, glowing skin starts with a strong barrier. Signs like dehydration, redness or sensitivity often point to barrier disruption — and even issues like pigmentation or breakouts can stem from this. To help restore balance, light, biomimetic oil-based moisturisers such as the Dr. Spiller Collagen Cream or Rinazell Lacteal Active Substance Cream can be a good addition to any skincare ritual. They reduce moisture loss and provide lasting hydration, helping to prevent the cascade of skin issues that often follow dehydration.
