Ceramides are sphingolipids, lipid molecules that are found in high concentrations within cell membranes in all four layers of the epidermis. They are, however, particularly numerous in the stratum corneum, the epidermal layer closest to the surface of the skin. Ceramides play an important role in the chemistry of our skin: they hold cells together, forming a protective layer that plumps the skin and retains moisture. Unfortunately, their numbers naturally decrease with age, causing a number of negative consequences. Nine different ceramides have been found in skin, and you can find some of these in skincare products; some derived from plants and some synthetically produced.
On the skin's surface, ceramides bind dead cells together, so as to limit the loss of water and prevent the penetration of harmful substances such as pollution, tobacco, dust and UV rays. When the stratum corneum lacks ceramides, the skin loses water and becomes more vulnerable to those harmful environmental stresses. Being dehydrated and irritated, the skin becomes highly sensitive. Ceramide-rich treatments are formulated to maintain the skin's moisture level and help repair it, while also strengthening the skin's natural barrier. Regular use can also help to prevent further problems arising in the future. Their topical use comes recommended by dermatologists for those who suffer from skin complaints such as eczema, psoriasis or atopic dermatitis, as it has been found that people suffering from these skin complaints have lower levels of ceramides occuring naturally.