Structure and Function of Ceramides
Ceramides represent approximately 50% of lipids in the stratum corneum and are essential for the structural integrity of the skin barrier. They are synthesized in the epidermis from sphingosine and fatty acids and are integrated into the lipid bilayer together with cholesterol and free fatty acids.
Ceramides form a waterproof layer that prevents moisture loss and protects against exogenous agents. They provide structural stability to the lipid bilayer through formation of hydrogen bonds and van der Waals interactions between molecules.
Ceramides and Skin Diseases
Reduced ceramide concentration is associated with various dermatological conditions, including atopic dermatitis and xerosis. In these conditions, the lipid bilayer is impaired, leading to increased TEWL, reduced hydration and increased sensitivity to irritants.
Topical Application of Ceramides
Topical application of ceramides restores the lipid bilayer and improves barrier function, leading to reduced transepidermal water loss and improved hydration. Synthetic and plant ceramides used in cosmetic formulas demonstrate similar efficacy to natural ceramides in maintaining the skin barrier.
Ceramides are combined with cholesterol and free fatty acids in optimal ratios (3:1:1) for maximum efficacy. This combination, known as the “lipid trio”, restores the structural integrity of the lipid bilayer and improves barrier function.
Application in Cosmetic Formulas
In Collagena Professional® products, ceramides are integrated into formulas that restore and maintain the skin barrier. They act in synergy with other lipid components, such as phospholipids and cholesterol, to achieve optimal barrier function and skin hydration.
