The Skin Barrier Lipid Matrix — What It Is, What It Does, and Why Structure Is the Point
Skincare has spent a decade talking about ceramides. What it has talked about less — and understood less clearly — is what ceramides actually belong to: a structural architecture that only functions when the whole thing is intact.
The skincare industry turned ceramides into a hero ingredient. The barrier never treated them that way. The lipid matrix of the skin barrier is not a ceramide story, or a cholesterol story, or a fatty acid story. It is a structure story. The components are only meaningful in the context of how they organise. And that organisation — the reason it exists, how it functions, and what happens when it becomes disorganised — is what this article explains.
What the skin barrier lipid matrix is
The outermost layer of skin — the stratum corneum — is made of two things: flattened, protein-filled skin cells called corneocytes, and the lipid-filled space between them. The lipid matrix is that intercellular space.
Not lipid as in oiliness, or lipid as in moisturisation. Lipid as in a highly organised, multilayered structural system that fills every gap between cells in the outer skin — and whose job is to slow the movement of water out of the body to a rate the skin can sustain.
The skin barrier lipid matrix is the organised, multilayered system of lipids — primarily ceramides, cholesterol, and free fatty acids — that occupies the intercellular spaces of the stratum corneum. These lipids are not randomly distributed. They are arranged in thin, repeating stacked layers that run parallel to the skin surface. This layered organisation creates a winding, indirect pathway through which water must travel to leave the body, significantly reducing the rate of passive water loss. The lipid matrix is the primary structural determinant of skin barrier integrity and transepidermal water loss (TEWL).
The lipid matrix is not a coating on the surface of skin. It is inside the stratum corneum — woven into the architecture of the outer skin at a cellular level. And unlike sebum, which is produced by glands and sits on the surface, the matrix lipids are synthesised within the skin cells themselves and released into the spaces between cells as those cells complete their journey to the surface. They are structural, not secreted. They belong to the barrier itself.
This distinction matters because it changes what kind of problem matrix disruption is. When the lipid matrix is depleted or disorganised, the issue is not that the skin's surface is dry. The issue is that a load-bearing structural component of the barrier architecture has been compromised. Restoring surface hydration addresses the experience. Restoring matrix organisation addresses the cause.
→ Why Your Skin Feels Tight After Washing — what barrier disruption actually signalsThe brick-and-mortar structure
The most widely used description of the stratum corneum's architecture is the brick-and-mortar model. It is a useful analogy — not because it is poetic, but because it is structurally accurate.
In this model, the corneocytes are the bricks: flat, dense, protein-filled cells stacked in overlapping layers. The lipid matrix is the mortar: the material filling every space between and around those cells. Remove the mortar from a brick wall and the bricks remain — but the wall no longer holds. It is the mortar that makes the structure coherent and functional. In skin, the lipid matrix performs that binding and sealing role.
Water cannot move straight through the stratum corneum. The corneocytes themselves are largely impermeable — protein-dense and tightly packed. But water does not try to move through them. It moves around them, through the intercellular spaces. The lipid matrix, arranged in repeating layers within those spaces, is what it has to navigate. Each layer presents a new obstacle. Water must work its way around and between each one, creating a route so indirect and so structurally resistant that the rate of water passage is dramatically reduced. This is how an intact lipid matrix maintains hydration within the skin — not by being impermeable, but by being architecturally resistant. The path is long enough that most water stays inside [Elias, 2005].
The mortar analogy is also useful for understanding what disruption looks like. When the lipid matrix is degraded — through repeated chemical extraction, enzymatic disruption, or impaired synthesis — it is not the bricks that fail. The bricks (corneocytes) remain. But the mortar between them becomes thin, irregular, or absent in places. The wall develops gaps. Water that previously had to navigate a tortuous, resistive route can now find shorter paths through. The rate of water loss increases. The barrier's functional integrity — its ability to regulate what passes through it — is reduced, even though the cellular architecture of the stratum corneum looks largely unchanged.
This is why the lipid matrix is the primary barrier to transepidermal water loss, not the corneocytes themselves. The cells are structural. The lipids between them are functional. Both are necessary. But when it comes to barrier permeability — the question of how much water the skin is losing — the lipid matrix is the governing variable.
The three components — as a system, not a list
The lipid matrix is composed of three primary lipid types: ceramides, cholesterol, and free fatty acids. In human stratum corneum, these occur in approximately equimolar proportions — roughly one-third each by molar ratio, though the precise distribution varies by body site, age, and skin health status [Lampe et al., 1983].
This three-part composition is not incidental. It is functionally necessary. Each component plays a distinct role that the others cannot replicate, and the structure the three form together depends on the balance between them. Change that balance — reduce ceramides without compensating, or supplement ceramides without cholesterol and fatty acids — and the layered architecture that makes the matrix functional does not form correctly.
When ceramides, cholesterol, and free fatty acids are present in their correct proportions, they organise into the repeating layered structure that makes the matrix function. Change the ratio and the structure changes. The layers become irregular, incomplete, or replaced by different arrangements that are less resistant to water passage. This is why ceramide-only supplementation — whether topical or via barrier repair formulations that ignore cholesterol and fatty acid balance — does not automatically restore barrier function. All three components, in appropriate proportion, are required for the architecture to form [Elias and Feingold, 2001].
The lipid matrix does not care which ingredient receives the marketing budget. It only functions when the structure is intact. Ceramides are the most prominent component — but the barrier is built from the relationship between all three, not from ceramides alone.
The skincare category has largely told a ceramide story. Ceramide content, ceramide types, ceramide concentration — these are the metrics that have been communicated to consumers. The cholesterol and fatty acid contributions to the same system have been significantly underrepresented. This is a communication failure that matters biologically: the system only functions as a system. Ceramides alone are not a complete lipid matrix.
What ceramides do
Ceramides are the dominant lipid class in the stratum corneum by weight — they constitute approximately 50% of total stratum corneum lipid content in healthy skin [Coderch et al., 2003]. There are multiple ceramide subtypes, and their roles within the matrix are not interchangeable — different subtypes occupy specific structural positions within the layered system.
Ceramides in the skin barrier context are the primary structural component of the layered lipid matrix. Their long fatty acid tails interleave with cholesterol molecules in each layer, creating the packing density that makes the structure resistant to water passage. There are multiple ceramide subtypes, and their roles within the matrix are not interchangeable. One subtype — sometimes called Ceramide-1 — is structurally distinct: it spans across multiple layers, acting as a linker that holds successive layers together and prevents the structure from separating under osmotic stress [Schade et al., 1996].
Ceramides decline with age — measurably and progressively. Studies of stratum corneum ceramide content across age groups show consistent reductions from the fourth decade onward, with the rate of decline accelerating in mature skin [Rogers et al., 1996]. The consequence is not only reduced total lipid content but a less dense, less regular layered structure. This is part of the physiological basis for why mature skin experiences higher baseline TEWL and slower barrier recovery than younger skin — the structural material the matrix is built from is being produced at a lower rate.
In intact skin, ceramide production is continuous. Cells in the lower layers of the epidermis produce ceramide precursors that are packaged into small lipid-filled structures and released into the spaces between cells as those cells reach the outer skin. Local enzymes then convert these precursors into the mature ceramide forms present in the matrix. This is why the enzymatic environment of the stratum corneum — particularly its pH, which governs the activity of those enzymes — is not a cosmetic detail. It is part of the ceramide production pathway.
→ What TEWL Is — and how it reflects lipid matrix integrityWhat cholesterol does
Cholesterol is the most under-communicated component of the lipid matrix in public skincare discourse. It contributes approximately 25% of stratum corneum lipid content [Lampe et al., 1983] and plays a role that ceramides, by themselves, cannot perform: it controls the flexibility of the layered structure.
Cholesterol in the stratum corneum acts as a flexibility regulator within the lipid matrix. Without cholesterol, the ceramide-rich layers tend toward a rigid, brittle state — structurally ordered but too inflexible to support the enzymatic activity required for barrier maintenance and repair. Cholesterol inserts between the lipid chains and introduces just enough flexibility to keep the structure functional without losing its organisation. This is not a cosmetic property — it is a physiological requirement. A matrix without adequate cholesterol cannot adapt to osmotic changes or sustain the enzymatic processing that barrier repair depends on [Feingold, 2007].
Cholesterol also plays a direct role in barrier repair. When the stratum corneum detects elevated TEWL — the primary signal that the matrix has been disrupted — it initiates a repair cascade. Cholesterol synthesis in the epidermis is specifically upregulated in response to barrier disruption; studies applying cholesterol synthesis inhibitors to disrupted skin find that repair is significantly slowed, demonstrating that cholesterol availability is a rate-limiting factor in the repair process, not an incidental one [Proksch et al., 1993].
This has practical implications that skincare has largely not communicated. When the lipid matrix is disrupted — by repeated surfactant exposure, for instance — the repair process requires ceramides, cholesterol, and free fatty acids to be synthesised and organised simultaneously. Topical approaches that deliver ceramides alone, without the cholesterol component, are providing one input into a three-component repair system. The system cannot achieve its intended structure with one input absent.
What free fatty acids do
Free fatty acids complete the lipid triad and perform two functions that the other two components cannot: they govern the pH of the spaces between skin cells, and they provide the structural precision that makes the lipid layers tightly packed and resistant.
Free fatty acids in the stratum corneum are primarily long-chain saturated fatty acids — the same chain-length category as the fatty acids in ceramides. Within the layered matrix, their chains interleave tightly with ceramide chains, contributing to the structural packing that makes the matrix resistant to water passage. Their second function is equally important: free fatty acids are the principal source of the slightly acidic pH — typically 4.5 to 5.5 — maintained at the skin surface and throughout the stratum corneum. This acidic environment is not a cosmetic property. It is the operational condition for the enzymes responsible for desquamation and for those that synthesise ceramides from their precursors [Fluhr et al., 2001].
The fatty acid contribution to stratum corneum pH is one of the most physiologically significant functions in the outer skin, and one of the least discussed in consumer skincare education. The slightly acidic environment that fatty acids help create and maintain is the condition under which the stratum corneum's enzymatic processes run correctly. When that pH is disrupted — shifted toward alkaline conditions by high-pH cleansers or anionic surfactant exposure — the enzymatic activity required to convert lipid precursors into mature ceramides slows significantly. The disruption is not only to current matrix integrity. It impairs the enzymatic machinery that the barrier needs to rebuild itself.
Free fatty acid depletion is therefore a compounding disruption. Lose fatty acids from the matrix, and two things happen: the layered structure loses part of its scaffolding, and the pH environment shifts in a direction that makes rebuilding that scaffolding harder. Recovery from fatty acid depletion is consequently slower and less complete than recovery from ceramide depletion alone — the fatty acids are not just a structural component, they are an environmental prerequisite for the system that synthesises all three.
→ What Anionic Surfactants Do to the Skin Barrier — including how surfactant exposure depletes fatty acids and disrupts stratum corneum pHWhy organisation is the point
The lipid matrix is not a stockpile of lipid ingredients. It is an organised structure. And the distinction between lipids being present and lipids being correctly organised is the most important distinction in understanding how the barrier actually works.
A useful way to frame this: imagine the three components as construction materials — bricks, mortar, and scaffolding. The materials can be present in the right quantities, but if they are not assembled correctly — if the bricks are piled without mortar, or the scaffolding is in the wrong position — the wall does not stand. The same materials, correctly assembled, produce a load-bearing structure. Incorrectly assembled, they produce a pile.
The lipid matrix is the assembled version. It is not simply ceramides, cholesterol, and free fatty acids sitting in the spaces between cells. It is those three components, in specific ratios, organised into repeating layered structures stacked parallel to the skin surface, with each component occupying a precise position within each layer. That organisation is what creates the winding, resistive path described earlier. That organisation is what makes the barrier resistant to water passage. That organisation is what is disrupted when the barrier is damaged — not simply the quantities of individual lipids.
The layered structure of the stratum corneum lipids can be measured at a molecular level, and that measurement tells us something important: the structure exists in two distinct packing arrangements, both present in healthy skin. Disruption of either arrangement — through lipid extraction, temperature change, or altered lipid ratios — produces measurable changes and increased water permeability. Research applying individual lipid classes to lipid-depleted stratum corneum showed that ceramides, cholesterol, and fatty acids applied separately did not restore the structure; only the combination of all three, in appropriate proportions, reconstituted the normal layered pattern and reduced TEWL toward baseline [Bouwstra et al., 2003].
The barrier is built from relationships between components, not individual ingredients. This is the most important finding in lipid matrix science for understanding why single-ingredient approaches to barrier support are structurally incomplete. It is not that ceramides are not important — they are the dominant component by mass. It is that the matrix ceramides belong to requires all three inputs to take the form that makes it functional. The structure is the point. The ingredients are only meaningful insofar as they produce the structure.
The practical implication runs in both directions. For disruption: what damages the barrier is not primarily lipid loss but structural disorganisation. Solvents, surfactants, and mechanical disruption extract lipids in ways that destroy the layered arrangement, not just deplete the quantity. For recovery: what restores barrier function is the re-establishment of that layered organisation — which requires the right lipids, in the right ratios, processed by a functional enzymatic system operating in the right pH environment. Organisation is not a bonus outcome. It is the only outcome that restores function.
Lipid matrix, TEWL, and barrier integrity
Transepidermal water loss — the rate at which water vapour passes passively from the body through the outer skin to the surrounding environment — is the functional expression of lipid matrix integrity. The two are directly linked, and understanding how makes TEWL more than a measurement: it becomes a way of reading the matrix's structural state.
When the lipid matrix is intact and correctly organised, TEWL is regulated within a normal physiological range — approximately 5 to 15 g/m²/h on facial skin under controlled conditions, reflecting the resistance of the layered structure [Pinnagoda et al., 1990]. This is not zero water loss — some passive movement of water outward is normal and necessary for the stratum corneum's own enzymatic function. But the rate is low enough that the skin's internal water reserves, and the water-binding capacity of the natural moisturising factor (NMF) within corneocytes, can maintain adequate hydration in the outer layers.
When the lipid matrix is disrupted — whether through lipid extraction by surfactants, mechanical abrasion, inflammatory skin conditions, or impaired lipid synthesis — the layered structure becomes irregular. The indirect, resistive pathway water must travel is shortened or bypassed. Water moves through the stratum corneum more easily and more rapidly. TEWL rises. The degree of elevation reflects the degree of structural disorganisation: minor disruption produces modest, temporary TEWL elevation; sustained or severe disruption produces more significant and more persistent elevation.
The relationship between lipid matrix integrity and TEWL is not simply correlational — it is causal. Studies using selective lipid depletion techniques (including organic solvent extraction, tape-stripping, and surfactant challenge) demonstrate that TEWL elevation tracks precisely with the degree of structural disruption as confirmed by imaging and molecular analysis. Conversely, studies applying mixtures of ceramides, cholesterol, and free fatty acids to disrupted skin show that TEWL reduction tracks with the degree to which structural organisation is reconstituted. The measurement — grams of water per square metre per hour — is reading the structure's functional state [Fluhr and Darlenski, 2009].
This makes TEWL not just a marker of dehydration but a structural indicator. A TEWL elevation tells you something about the lipid matrix — not what caused the disruption, and not exactly which component is depleted, but that the structure is not functioning at its full regulatory capacity. A TEWL that remains within normal range, even after a cleansing or environmental challenge, is evidence that the matrix's organisation has been largely preserved. TEWL is, in this sense, the matrix's report on its own integrity.
Barrier integrity, as a concept, is often used loosely in skincare. In physiological terms it refers specifically to the stratum corneum's capacity to regulate what passes through it — water outward, and environmental substances inward. That capacity is determined primarily by the lipid matrix. An intact matrix means an intact barrier. A disorganised matrix means a compromised barrier. The degree of TEWL elevation is the most direct non-invasive measure of how significant that compromise is.
→ What TEWL Is — Transepidermal Water Loss and the Skin BarrierWhat happens when the matrix becomes disorganised
Matrix disorganisation does not produce a single immediate symptom. It produces a sequence of consequences that unfold on different timescales — and the experience that eventually becomes visible or uncomfortable is often many steps removed from the structural event that initiated it.
The sequence begins with structural disorganisation: the repeating layered structure loses its regularity. This can occur through lipid extraction (surfactants, solvents), mechanical disruption (abrasion, over-exfoliation), enzymatic abnormality (conditions like eczema where barrier enzyme function is impaired), or progressive lipid synthesis decline (age-related ceramide reduction). The specific source determines the rate and severity, but the structural consequence is the same: the resistive pathway through the matrix becomes shorter, and TEWL increases.
Elevated TEWL is the signal that triggers the barrier repair cascade. The skin detects water loss above threshold and responds by releasing stored lipid precursors into the spaces between cells, where local enzymes convert them into ceramides, cholesterol, and fatty acids for matrix reconstruction. This process has been covered in detail in Skin Barrier Repair vs Preservation and What Is TEWL; what matters here is that the trigger is lipid matrix disorganisation, and the repair response is specifically directed at restoring the layered structure.
While repair is running, the barrier is functioning at reduced capacity. Water is leaving faster than normal. The corneocytes, which require adequate hydration to remain flexible, begin to lose plasticity. The skin surface may feel tight — not because the skin is physically tighter, but because dehydrated corneocytes are less supple and create a different surface tension. If this dehydration is significant or prolonged, fine lines become more apparent and texture may roughen.
A disrupted lipid matrix is not only losing water faster than normal. The same structural change that allows water to pass outward more easily also allows substances to penetrate inward more easily. The layered structure that resists water leaving also resists environmental substances entering. When it is disorganised, that resistance is reduced in both directions. Potential irritants — surfactant residues, environmental pollution particles, allergens — can reach deeper layers of the skin, where immune cells are more accessible. This is the mechanistic basis for the increased reactivity that often accompanies barrier compromise: the barrier is not only losing water — it is becoming more permeable to the inputs that activate inflammatory responses [Proksch et al., 2008].
When disruption is acute and infrequent, the repair cascade runs to completion between events and the matrix restores close to its prior state. When disruption is repeated — at a frequency that exceeds the repair cycle's completion time — recovery is partial rather than complete. The matrix baseline shifts: the layered structure the skin maintains between disruption events is less organised than it would be with adequate recovery time. TEWL at the skin's mid-cycle baseline (not just immediately post-disruption) is measurably higher than in non-disrupted skin. Reactivity increases. The margin between comfortable and reactive narrows.
Over a longer timescale, chronic matrix insufficiency produces what might be described as a structural baseline change. This is not a single dramatic event. It is the cumulative effect of the repair cycle operating under conditions where it cannot fully complete — where the frequency of disruption, or the age-related decline in ceramide synthesis, or both, mean that the matrix is never given the conditions to reach its optimal organisation. The skin that has settled into persistent tightness, that finds an increasing number of products irritating, that no longer responds to moisturiser the way it once did, is often a skin operating from a compromised lipid matrix baseline.
→ Skin Barrier Repair vs Preservation — why disruption frequency changes the picture → How Cleansing Damages the Skin Barrier — one of the most repeated routes to lipid matrix disruptionCedar of the Forest — and the lipid matrix question
The lipid matrix article in the Cedar knowledge cluster is not here to explain what Cedar contains. It is here because the matrix is what Cedar's formulation philosophy is about.
Understanding the lipid matrix changed the formulation question. Not: what should a cleanser contain? But: what is daily cleansing doing to the structural lipid environment the barrier depends on?
The cleansing step is the most repeated point of contact between a product and the lipid matrix. Sebum on the skin surface and the structural lipids within the matrix share the same chemical environment. A cleansing mechanism that acts on one of them does not automatically leave the other untouched.
When Cedar was being formulated, the starting point was this question: does the cleansing mechanism impose a structural cost on the lipid matrix, or does it not? That question only becomes answerable once you understand what the matrix is — a layered system that functions through organisation, not just the presence of individual lipids — and what disrupts it.
The lipid matrix framework made a vague concern specific. And a specific question is one that can be answered by formulation.
Frequently asked questions
What is the skin barrier lipid matrix?
The skin barrier lipid matrix is the organised system of lipids — primarily ceramides, cholesterol, and free fatty acids — that fills the spaces between skin cells in the outermost layer of skin, the stratum corneum. These lipids are not distributed randomly. They are arranged in thin, repeating stacked layers that run parallel to the skin surface. This layered organisation creates a winding, indirect path through which water must travel to leave the body, significantly slowing passive water loss. The lipid matrix is the primary structural determinant of how well the skin barrier retains water and regulates what passes through it.
What is the lipid matrix in skin made of?
The lipid matrix in healthy human stratum corneum is composed of approximately equal proportions of three lipid classes: ceramides (roughly 50% by weight), cholesterol (approximately 25% by weight), and free fatty acids (approximately 15–20% by weight). Each plays a distinct role. Ceramides form the primary scaffolding of the layered structure. Cholesterol controls flexibility and prevents the structure from becoming too rigid. Free fatty acids contribute to structural packing and are the principal source of the acidic pH that governs the enzymatic environment of the stratum corneum. All three must be present in appropriate proportions for the layered organisation to form correctly and for the matrix to function as a barrier.
What do ceramides do in the skin barrier?
Ceramides are the dominant lipid class in the stratum corneum by weight and form the primary scaffolding of the layered structure that makes up the lipid matrix. Their long fatty acid chains interleave with cholesterol molecules in each layer, creating the packing density that makes the structure resistant to water passage. One ceramide subtype acts as a structural linker that spans across multiple layers, holding them together and preventing separation under osmotic stress. However, ceramides do not function in isolation: the layered structure they contribute to requires cholesterol and free fatty acids in appropriate proportions to form correctly. Ceramide supplementation without the cholesterol and fatty acid components does not fully reconstitute the layered organisation or restore barrier function to baseline.
What does cholesterol do in the skin barrier?
Cholesterol acts as a flexibility regulator within the lipid matrix of the stratum corneum. Without cholesterol, the ceramide-rich layers tend toward a rigid, brittle state that is structurally ordered but less able to support the enzymatic processes required for barrier maintenance and repair. Cholesterol inserts between lipid chains and introduces just enough controlled flexibility to keep the structure functional. Cholesterol is also directly involved in barrier repair: cholesterol synthesis in the epidermis is specifically upregulated after barrier disruption, and inhibiting that synthesis slows repair significantly. This makes cholesterol a rate-limiting input in the repair cascade, not simply a structural component of the resting matrix [Proksch et al., 1993].
What do free fatty acids do in the skin barrier?
Free fatty acids perform two functions in the stratum corneum: they contribute to the structural packing of the lipid matrix, and they are the principal source of the acidic pH — typically 4.5 to 5.5 — maintained at the skin surface and throughout the stratum corneum. This acidic environment is not a cosmetic property. It is the operational condition for the enzymes that govern cell shedding, ceramide production, and barrier repair. When free fatty acids are depleted — by surfactant extraction or other disruption — both the structural integrity of the matrix and the enzymatic environment for repair are compromised simultaneously. This makes fatty acid depletion a compounding disruption: the matrix loses a structural component and the conditions that enable rebuilding it become less favourable at the same time.
Why does the organisation of the lipid matrix matter more than individual lipid ingredients?
The functional barrier properties of the lipid matrix — its resistance to water passage, its regulation of what moves through the stratum corneum — arise from the organised, layered arrangement of all three components together, not from the presence of any individual lipid. Research applying ceramides, cholesterol, and free fatty acids individually to lipid-depleted stratum corneum showed that no single component restored the structure or fully restored barrier function; only the combination of all three in appropriate proportions reconstituted the normal layered pattern and produced the corresponding TEWL reduction [Bouwstra et al., 2003]. Adding ceramides to a disrupted barrier addresses one input into a three-component system. The structure the ceramides belong to requires all three components to assemble correctly. Organisation is not a downstream outcome of lipid presence — it is the state that makes the lipids functional as a barrier.
What happens when the skin barrier lipid matrix is disrupted?
When the lipid matrix is disrupted — through lipid extraction, mechanical abrasion, or impaired synthesis — the layered structure becomes irregular. The indirect, resistive path through which water must travel becomes shorter, and transepidermal water loss (TEWL) increases. Elevated TEWL triggers the barrier repair cascade. While repair is underway, the barrier operates at reduced capacity: water leaves faster than normal, skin cells lose hydration and flexibility, and the skin may feel tight or rough. Additionally, the same structural change that allows water out more easily also allows environmental substances — irritants, allergens — to penetrate inward more easily, which reduces the reactivity threshold of the skin. When disruption is repeated at a frequency that exceeds the repair cycle's completion time, the matrix never fully recovers between events. The skin operates from a structurally compromised baseline, characterised by chronically elevated TEWL, persistent dehydration, and progressively increased sensitivity.
Why is the skin barrier compared to a brick-and-mortar structure?
The brick-and-mortar model describes the stratum corneum's structural architecture accurately. The corneocytes — flattened, protein-filled skin cells — are the bricks: stacked in overlapping layers. The lipid matrix filling the intercellular spaces between them is the mortar: the structural material that seals the gaps and gives the overall architecture its functional coherence. As with a wall, removing the mortar leaves the bricks intact but the structure non-functional. In skin, when the lipid matrix is depleted or disorganised, the cellular architecture of the stratum corneum is largely unchanged, but the matrix's ability to regulate water loss and barrier permeability is compromised. The model was introduced by Peter Elias in 1983 and remains the standard descriptive framework in dermatological and barrier science literature [Elias, 1983].
References
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- Coderch, L., López, O., de la Maza, A., and Parra, J.L. "Ceramides and skin function." American Journal of Clinical Dermatology, Vol. 4, No. 2, 2003, pp. 107–129.
- Elias, P.M. "Epidermal lipids, barrier function, and desquamation." Journal of Investigative Dermatology, Vol. 80, Suppl. 1, 1983, pp. 44s–49s.
- Elias, P.M. "Stratum corneum defensive functions: an integrated view." Journal of Investigative Dermatology, Vol. 125, No. 2, 2005, pp. 183–200.
- Elias, P.M., and Feingold, K.R. "Coordinate regulation of epidermal differentiation and barrier homeostasis." Skin Pharmacology and Applied Skin Physiology, Vol. 14, Suppl. 1, 2001, pp. 28–34.
- Feingold, K.R. "Thematic review series: skin lipids. The role of epidermal lipids in cutaneous permeability barrier homeostasis." Journal of Lipid Research, Vol. 48, No. 12, 2007, pp. 2531–2546.
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- Fluhr, J.W., and Darlenski, R. "Skin water-barrier function in acute and chronic wounds." Current Problems in Dermatology, Vol. 38, 2009, pp. 35–48.
- Lampe, M.A., Burlingame, A.L., Whitney, J., Williams, M.L., Brown, B.E., Rosenthal, E., and Elias, P.M. "Human stratum corneum lipids: characterization and regional variations." Journal of Lipid Research, Vol. 24, No. 2, 1983, pp. 120–130.
- Pinnagoda, J., Tupker, R.A., Agner, T., and Serup, J. "Guidelines for transepidermal water loss (TEWL) measurement." Contact Dermatitis, Vol. 22, No. 3, 1990, pp. 164–178.
- Proksch, E., Feingold, K.R., Man, M.Q., and Elias, P.M. "Barrier function regulates epidermal DNA synthesis." Journal of Clinical Investigation, Vol. 91, No. 6, 1993, pp. 2661–2669.
- Proksch, E., Brandner, J.M., and Jensen, J.M. "The skin: an indispensable barrier." Experimental Dermatology, Vol. 17, No. 12, 2008, pp. 1063–1072.
- Rogers, J., Harding, C., Mayo, A., Banks, J., and Rawlings, A. "Stratum corneum lipids: the effect of ageing and the seasons." Archives of Dermatological Research, Vol. 288, No. 12, 1996, pp. 765–770.
- Schade, H., Marchetti, A., and Elias, P.M. "Permeability barrier repair after tape-stripping: lipid repletion allows barrier recovery." Archives of Dermatological Research, Vol. 288, No. 7, 1996, pp. 390–395.