Ingredient Library
Ceramides
Sphingolipid
The mortar between your skin cells. Without it, everything leaks.
Ceramides make up around 50% of the lipid matrix in your stratum corneum. They are the quiet structural workhorses that keep your barrier intact, and the ingredient category most people skip, but probably need the most.
INCI
Ceramide NP
Solubility
Oil soluble
pH Range
5.0–7.0
Effective Range
0.1–5%
01: What Is It
The Skin’s Own Structural Lipid
Ceramides are sphingolipids: long-chain fatty acids linked to a sphingosine backbone. There are at least twelve identified ceramide classes in skin (NP, AP, EOP, NS, and others), each contributing to the layered, lamellar structure that holds the outer barrier together.
They are naturally produced by the skin via the lamellar body secretion pathway, but levels decline with age, UV exposure, over-cleansing, and aggressive use of harsh actives. As ceramides drop, the lipid matrix thins and becomes disorganised.
Think of the barrier as brick and mortar: corneocytes are the bricks; the lipid matrix is the mortar, roughly 50% ceramides, 25% cholesterol, and 15% free fatty acids. When this ratio is disrupted, transepidermal water loss (TEWL) rises, sensitivity increases, and skin becomes reactive, tight, and easily irritated.
Why It Matters
The lipid ratio matters as much as the ceramide percentage. Look for formulas that approximate the skin's natural 3:1:1 ratio of ceramides : cholesterol : fatty acids in serious barrier-repair moisturisers.
02: Mechanism
How It Rebuilds the Barrier
Ceramides are structural rather than “active”: they don’t signal, stimulate, or trigger dramatic reactions. They quietly fill in what’s missing, rebuilding the lipid architecture so everything else can function normally.
One: TEWL Reduction
TEWL Reduction
Ceramides fill the intercellular space between corneocytes, creating a continuous, ordered lipid barrier that slows water diffusion to the surface. In compromised barriers, moisturisers containing ceramides have been shown to reduce TEWL by roughly 30–50%, helping skin hold onto its own water.
Two: Microbiome Protection
Microbiome Protection
An intact ceramide-rich barrier keeps pathogens out and supports a balanced community of commensal microbes. When ceramides are depleted and the barrier is leaky, opportunistic species like Staphylococcus aureus can overgrow, driving inflammation and flare-ups in conditions such as eczema and acne.
Three: Sensitivity Reduction
Sensitivity Reduction
By restoring barrier integrity and reducing micro-cracks in the lipid matrix, ceramides help cover and protect superficial nerve endings. This directly lowers the perception of stinging, burning, tightness, and reactivity to other actives and environmental triggers.
Why It Matters
Ceramides on their own cannot fully restore barrier structure. They need cholesterol and free fatty acids in the right proportions; a good ceramide moisturiser is always a lipid system, not just a ceramide hit.
03: Concentrations
Dose Is Less Important Than Ratio
For ceramides, concentration is a blunt tool. Efficacy depends more on the overall lipid ratio and how those lipids are delivered. Formulas that organise ceramides, cholesterol, and fatty acids into lamellar vesicles can dramatically improve penetration and barrier repair compared with the same percentage dispersed in a simple cream.
0.1–0.5%
Maintenance and sensitive-skin support. Enough to continuously top up the lipid matrix and signal that the barrier environment is being supported.
0.5–2% (Sweet Spot)
Clinically studied range for barrier repair and eczema-prone skin. This is where most well-formulated moisturisers land when they prioritise barrier function.
2–5%
Intensive repair for very dry, eczema-prone, or post-procedure skin. Often found in specialist or short-course treatments designed to quickly rebuild a severely compromised barrier.
Above 5%
Rarely used in leave-on products. Formulation challenges and texture issues increase significantly, with diminishing returns compared to optimising the lipid ratio and delivery system.