Lipid barrier – protective layer and moisture balance of the skin

The lipid barrier is part of the stratum corneum and consists mainly of ceramides, cholesterol, and free fatty acids. It reduces transepidermal water loss (TEWL) and protects against irritants and microorganisms.

Structure and function

In the "brick-mortar" structure, corneocytes (bricks) are embedded in lamellar lipid layers (mortar). This arrangement determines the permeability and elasticity of the skin and regulates TEWL – a key metric for barrier health.

Relevance for cosmetics

Topical barrier lipids can stabilize damaged structures. Ceramides (including long chains) in particular have been shown to contribute to barrier repair; suitable formulations improve hydration and skin comfort.

Factors that weaken the lipid barrier

• Frequent/overly aggressive cleaning and surfactants
• Dry, cold air and UV radiation
• Incorrect care (too degreasing, high alcohol content)
• Inflammatory skin conditions (e.g. atopic dermatitis)

Rebuilding in nursing care

Products containing ceramides, cholesterol, linoleic acid, or squalane support the lipid matrix. Gentle cleansing, humectants, and daily UV protection reduce transepidermal water loss (TEWL) and promote barrier function.

Conclusion

A stable lipid barrier is the foundation of healthy skin. Cosmetic formulations that combine skin-identical lipids in a meaningful way measurably improve hydration and protective function.

Sources

1. Berdyshev E. (2024): Skin Lipid Barrier – Structure, Function & Metabolism (Review)
2. Schild J. (2024): Ceramides in Skin Barrier Function & Correct Formulation – Int J Cosmet Sci
3. Green M. (2022): Transepidermal Water Loss (TEWL) – Overview & Determinants
4. Akiyama F. (2024): Correlations of Skin Parameters & Ceramide Classes
5. Murphy B. (2022): Barrier Improvements with Lipid-Rich Topicals – Sci Rep