Ceramide Ag

Ceramide AG is a manufactured version of one of the lipids (fats) that occurs naturally in the outermost layer of human skin. Chemically it is a sphingolipid: a sphinganine backbone, also called dihydrosphingosine, joined to an alpha-hydroxy fatty acid. The INCI name is simply shorthand for those two building blocks rather than a brand, a grade or a strength.

The odd-looking name reflects a change in labelling. Ceramides used to be listed by number, and were renamed with letter codes so the label tells you exactly which molecule is in the jar. Skin builds its ceramides from four sphingoid bases, sphinganine, sphingosine, phytosphingosine and 6-hydroxysphingosine, each paired with a range of fatty acids, which is why so many differently named ceramides exist. Ceramide AG belongs to the sphinganine group; the more familiar Ceramide NP and Ceramide AP are built on phytosphingosine.

The EU cosmetic ingredient inventory lists it with three functions: skin conditioning, hair conditioning and humectant. It is not restricted or banned under EU or UK cosmetic regulation. In practice you will meet it in moisturisers, barrier creams, richer serums, cleansing balms and post-procedure products, and rarely on its own. Commercial ceramides are made synthetically or by fermentation rather than extracted from animal tissue, which keeps batches consistent. Whether a finished product is vegan depends on the whole formula, so check the brand's own statement. It appears in a smaller share of products than the headline ceramides.

Think of the skin's surface as brickwork. Flattened cells are the bricks and a mixture of lipids is the mortar packed between them. Ceramides make up roughly half of that mortar, with cholesterol and free fatty acids accounting for most of the rest. Together they stack into highly ordered sheets, and how tightly those sheets pack determines how much water escapes.

Each ceramide has a water-loving head and two long, water-repelling tails. The tails interlock with neighbouring lipids while the heads hydrogen-bond to one another, which is what draws the sheets into a dense, continuous layer. The exact shape of the sphingoid base and the fatty acid changes how neatly a given ceramide packs, and that is why formulators use several types together rather than relying on one. The alpha-hydroxy fatty acid in Ceramide AG carries an additional hydroxyl group available for that bonding.

Applied topically, ceramides are understood to slot into the existing lipid layers and top up what has been depleted by ageing, cold weather, harsh surfactants or over-exfoliation. Laboratory and clinical work on ceramide blends associates this with lower transepidermal water loss, the instrument measurement of moisture escaping through the surface. Skin then holds hydration for longer, feels less tight and looks smoother.

Ceramide AG is a supporting lipid rather than an active you build a routine around.

• Apply to skin that is still slightly damp after cleansing, so the lipids help hold that water in place.
• Use a ceramide moisturiser as the final step at night, or under sunscreen in the morning. It sits happily over water-based serums.
• Twice daily use is fine. There is no need to cycle it or build up tolerance.
• Look for it alongside cholesterol and fatty acids. The three lipids work as a set, and a blend of several ceramides is generally preferred to a single one.
• It pairs well with retinoids, exfoliating acids and vitamin C. Many people use a ceramide-rich cream on the nights they apply a stronger active, to keep skin feeling comfortable.
• Ceramides are stable across skincare pH levels and are not light-sensitive, so packaging matters less than it does for antioxidants.
• They are used at low percentages, so seeing Ceramide AG near the end of an ingredients list is normal.