Ingredient Library
Ceramides
EOP, NP, AP, NS, AS
The lipids that hold your skin barrier together — and the ones most disrupted by everything modern life throws at it.
They appear on nearly every moisturiser marketed for dry or sensitive skin. But ceramides are not a marketing invention — they are a structural component of your skin that depletes with age, stripping, and environmental stress. Here’s the biology, the types, and the formulation reality.
INCI
Ceramide EOP / NP / AP
Solubility
Oil soluble (lipid phase)
pH Range
Not pH-dependent
Effective Range
0.2–2%
01: What Is It
Your Skin’s Own Mortar
Ceramides are a family of waxy lipid molecules — not a single compound, but a class. In skin, they make up roughly 50% of the lipid content in the stratum corneum, the outermost layer. They sit between the corneocytes (skin cells) and bind them together into a coherent, semi-permeable barrier.
The naming convention is a mess: EOP, NP, AP, NS, AS, EOS — and the numbers (Ceramide 1, 2, 3…) are an older system still used on some labels. For formulation purposes, what matters is that synthetic ceramides closely mimic the skin’s own, and that they’re optimally delivered in an emulsion, not a water-only base.
Why It Matters
Ceramides are not humectants. They don’t pull water in. They prevent water from escaping — a structural distinction that changes how and where you layer them.
02: Mechanism
How the Barrier Works
Two mechanisms, one outcome. The barrier either holds or it doesn’t, and ceramides are the reason it does.
One
Lamellar body secretion
Keratinocytes package ceramides, cholesterol, and fatty acids into lamellar bodies and secrete them into the intercellular space as they move toward the surface. This self-assembly process creates the lipid bilayer structure that defines the stratum corneum. When ceramide synthesis is disrupted — by surfactants, UV, or inflammation — the bilayers become disorganised, and the barrier fails.
Two
Water loss prevention (TEWL)
Transepidermal water loss is the rate at which water passively diffuses out of skin into the environment. A healthy ceramide-rich barrier keeps TEWL low. Depleted ceramides mean higher TEWL — skin that feels tight, dry, and reactive even when you’re drinking enough water. Ceramides in a formula don’t eliminate TEWL, but they measurably reduce it by reinforcing the existing structure.
Three
Inflammatory signal modulation
Ceramides have a secondary role in cell signalling — some ceramide metabolites (particularly ceramide-1-phosphate) are involved in regulating inflammatory pathways. This is part of why ceramide-based formulas consistently perform well in clinical eczema and rosacea studies: they’re not just patching the physical barrier, they’re influencing the skin’s biochemical environment.
Why It Matters
TEWL is the metric that matters. If a moisturiser claims to hydrate but doesn’t reduce TEWL, it’s borrowing water, not building the barrier. Ceramides reduce TEWL.
03: Concentrations
Less Than You’d Expect
Ceramides are expensive ingredients, and effective concentrations are lower than the marketing suggests. 0.2% is enough to show measurable efficacy — the benchmark is not the number but the delivery system. An emulsion that gets ceramides into the lipid bilayer at 0.5% outperforms a serum with 2% that can’t get them there.
0.2–0.5%
Entry-level barrier support. Effective in a well-designed emulsion. The minimum that should appear on a label claiming ceramide benefit.
The Sweet Spot
0.5–1%
The clinical benchmark. Measurable TEWL reduction, barrier reinforcement, and suitable for sensitive and eczema-prone skin.
1–2%
Higher-end formulas and barrier-focused therapeutics. No irritation risk — ceramides are extremely well-tolerated at any concentration.
Above 2%
Technically fine, but cost-inefficient. The delivery system matters more than the percentage above this threshold.