Ceramides: The Barrier Ingredient That Changes Everything

What Ceramides Are

Ceramides are lipid molecules that form approximately 50% of the skin barrier — the stratum corneum. They sit in the spaces between your skin cells like mortar between bricks, preventing transepidermal water loss (TEWL) and blocking the entry of irritants, allergens, and pathogens.

The skin contains at least 12 distinct ceramide subtypes (Ceramide 1–12, or EOS, NS, NP, AP, AS, AH, NH, etc. in INCI nomenclature). Different subtypes have slightly different functions and orientations within the lipid bilayer.

What Happens When You Don't Have Enough

Ceramide depletion is behind almost every chronic skin concern:

• Eczema (atopic dermatitis) — ceramide content is significantly lower in eczema-affected skin
• Psoriasis — altered ceramide composition disrupts barrier function
• Dry skin — TEWL increases as ceramide levels decline with age
• Sensitive/reactive skin — compromised barrier allows irritants in and moisture out
• Acne — some evidence that barrier disruption worsens inflammation

Pro Tip: Over-cleansing, over-exfoliating, and

using harsh surfactants are the leading causes of ceramide depletion. Simplifying your routine is often the single most effective intervention.

How Topical Ceramides Work

For years, skeptics argued that ceramides were too large to penetrate the stratum corneum. The science is more nuanced: topical ceramides don't fully replace depleted ceramides at the molecular level, but they do help occlude the barrier, reduce TEWL, and appear to signal ceramide synthesis in keratinocytes.

Clinical evidence shows that ceramide-containing moisturisers significantly reduce TEWL and improve skin hydration in both normal and compromised barrier conditions.

Choosing a Ceramide Product

Look for formulations that include multiple ceramide types plus cholesterol and fatty acids — together these three form the complete lipid mixture that mimics the natural skin barrier ratio (approximately 3:1:1 by moles).

Products like CeraVe and La Roche-Posay Lipikar were among the first to incorporate this science. The field has expanded considerably since.

Find ceramide products in our ingredient database →

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