What does “healthy skin barrier” mean?
The outermost layer of the skin, known as the skin barrier, defends your body against external hazards while at the same time protects the water balance inside. The barrier function of the skin is located in the stratum corneum (SC), which consists of dead skin cells (corneocites) embedded in lipids (1, 2). These lipid bilayers consist predominantly of three different lipids: ceramides, cholesterol and free fatty acids. Intact skin barrier does not allow the entry of external aggressors and at the same time prevents the evaporation of water through the skin keeping it well-moisturized and hydrated.
What are the symptoms of disturbed skin barrier function?
Dryness, itching and inflammation may be a sign of impaired skin barrier. If left untreated, this may allow the entry of external allergens, microbes or irritants, leading to further inflammation and irritation of the skin, including to conditions like atopic dermatitis and eczema.
Why ceramides are important?
Being the predominant component in the “mortar” that seals skin cells, ceramides are an important factor for the integrity of the skin barrier. The concentration of ceramides in healthy individuals differs according to anatomical location and environmental influences, such as humidity and sun exposure. During the winter, less ceramides are found in skin exposed to low humidity, for example the face. Ceramides have also been found to decrease with age.
Atopic dermatitis is the disease that initially highlighted the importance of ceramides. A study in 1990, comparing the level of ceramides in healthy skin and in people with atopic dermatitis, showed lower levels of ceramides for atopic skin (1).
How to increase the concentration of ceramides in skin?
Ceramides can be replenished by topical application or by stimulating their synthesis.
It has been shown that moisturizers containing specific ingredients may affect the synthesis of ceramides. Some of the seemingly relevant ingredients are urea, canola oil, ammonium lactate, and linoleic acid.
Ceramides can also be applied topically in the form of lotions or creams. They are considered most beneficial when combined with cholesterol (which is also naturally present in skin).
What ceramides can do:
- Ceramides are a natural component of the skin barrier and help to protect and restore it;
- Ceramides work to protect the skin from external aggressors, thereby helping to prevent and resolve inflammation;
- Ceramides help to reduce transepidermal water loss (TEWL), making skin smoother and less prone to wrinkles;
- By keeping skin well-moisturized and free of inflammation ceramides help to prevent and reduce the visible signs of aging.
(1)PETER M. ELIAS M.D., Epidermal Lipids, Barrier Function, and Desquamation
(2)Jakob Mutanu Jungersted and Tove Agner, Eczema and ceramides: an update