Ceramides

Lipid molecules that repair and strengthen skin's moisture barrier.

Also known as: Ceramide NP, Ceramide AP, Ceramide EOP, Phytoceramides, Sphingolipids; INCI: Ceramide NP, Ceramide AP, Ceramide EOP, Ceramide NS, Ceramide AS.

What it is

Ceramides are naturally occurring lipids (fats) that make up roughly 50% of the skin barrier. They're found between skin cells and work alongside cholesterol and fatty acids to seal moisture in and irritants out. Synthetic and plant-derived versions are used in skincare to replenish what age, sun damage, and harsh cleansing deplete.

What it does

Ceramides fill gaps in the stratum corneum (outer skin layer), reducing transepidermal water loss (TEWL) and restoring barrier function. This reduces dryness, irritation, and sensitivity while improving skin's ability to retain hydration. They work best in combination with cholesterol and fatty acids—a ratio called the "3:1:1 ratio"—which mimics the skin's natural composition and maximizes efficacy.

The evidence

Strong clinical evidence supports ceramides for barrier repair and hydration; multiple randomized controlled trials show measurable improvements in TEWL, skin hydration, and irritation reduction within 2–4 weeks. Efficacy is highest when combined with cholesterol and free fatty acids in the correct ratio.

Best for

Dry, sensitive, compromised, or eczema-prone skin; anyone with a weakened barrier or using actives (retinoids, acids) that can compromise it.

Pairs well with

Cholesterol, fatty acids (to form the optimal 3:1:1 lipid complex), hyaluronic acid, glycerin, niacinamide, and soothing ingredients like centella or allantoin.

Use cautiously with

No major conflicts. Ceramides are compatible with most actives, though they're especially valuable when using drying ingredients like retinoids, vitamin C, or AHAs/BHAs.

Cautions

Generally very safe and non-irritating; no known sun-sensitivity or pregnancy concerns. Rare contact dermatitis in extremely sensitive individuals; patch-test if prone to reactions.