Ceramides

Ceramides are a family of lipids that make up a large share of the skin’s outermost layer. The usual way of picturing that layer is as a brick wall: the dead but structurally important skin cells are the bricks, and a mixture of ceramides, cholesterol and free fatty acids is the mortar between them. Ceramides are roughly half of that mortar, and without enough of them the wall leaks.

They are not one ingredient but a group. On an ingredients list you will see specific members named, such as Ceramide NP, Ceramide AP, Ceramide EOP and Ceramide NG, and often supporting compounds such as Phytosphingosine and Sphingosine, which the skin can use as building blocks. Older labels used a numbering system, so Ceramide 3 and Ceramide NP are the same thing.

Levels fall with age, with sun exposure, in cold and dry weather, and with over-washing or over-exfoliating. Skin that is short of ceramides tends to feel tight, look dull and flaky, sting when products are applied, and lose water quickly. That combination is what people usually mean when they describe a damaged barrier.

Ceramides in skincare are typically produced synthetically or by fermentation, and are used at low percentages, often well under 1%. This is not a case where more is better: what matters far more is that they appear alongside cholesterol and fatty acids in a sensible ratio, because the skin uses all three together.

They appear mainly in moisturisers, barrier creams, balms and cleansers designed for dry or reactive skin, and increasingly as a supporting element in products built around stronger actives.

The role of the ceramide layer is to keep water in and keep irritants out. It is a physical seal rather than an active process. When that seal is intact, water leaves the skin only slowly, and the substances skin meets during the day mostly stay on the outside. When it is depleted, water escapes faster and irritants find their way in more easily, which is why a compromised barrier produces dryness and reactivity at the same time.

Applying ceramides works on two levels. The immediate effect is straightforward replacement: they slot into the gaps in the existing lipid structure and help re-form the seal, so water loss slows and skin feels less tight fairly quickly. The second effect is slower and more interesting. Supplying ceramides and their precursors appears to support the skin’s own lipid production, so over time the barrier is better able to maintain itself rather than depending on what is applied.

The ratio point matters here. Research on barrier repair consistently indicates that ceramides work best alongside cholesterol and free fatty acids, in a proportion that resembles the skin’s own. A product delivering all three tends to outperform one delivering ceramides alone, which is why well-designed barrier creams read as a short list of lipids rather than a single headline ingredient.

Because none of this involves stimulating or exfoliating anything, ceramides carry essentially no adjustment period, and they suit every skin type, including oily skin, where barrier damage is common but often mistaken for something else.

Ceramides are a supporting ingredient rather than a treatment, and they are most useful when everything else in the routine is being demanding.

• Format matters more than percentage. Look for them in a moisturiser, cream or balm that stays on the skin, not in a cleanser that is rinsed away in thirty seconds.
• Look for the company they keep. Cholesterol and fatty acids alongside the ceramides, and supporting ingredients such as phytosphingosine, indicate a formula built around barrier repair rather than a single name on the front.
• When: morning and night, as often as you like. There is no tolerance to build and no reason to take breaks.
• Order in the routine: towards the end. Ceramide creams go after watery serums and actives, and before any facial oil or SPF.
• Pairs well with: everything, and particularly with retinoids, exfoliating acids and vitamin C, where they make the adjustment period considerably easier.
• Use them as the recovery step. If skin is stinging, tight or flaking after over-exfoliating, pausing the actives and using a ceramide cream twice daily for a week or two is the standard way back.
• Oily skin included. Oil and barrier lipids are not the same thing, and oily skin can be barrier-damaged. Choose a lighter ceramide lotion rather than skipping them.
• Apply to slightly damp skin after cleansing to hold a little more water in.