Skin is the largest organ in the body which consists of three main layers: epidermis, dermis, and hypodermis. The epidermis is the outermost layer of the skin and provides barrier function helping body against environmental hazards, such as ultraviolet (UV) radiation, chemical and physical insults, and microorganisms.
The epidermis is about 0.05–1 mm in thickness depending on body part. Keratinocytes are the predominant cells in the epidermis. Keratinocytes form three layers: stratum spinosum, stratum granulosum, and stratum corneum (SC) or the skin barrier (Figure 1).
Figure 1. Schematic of epidermis.
Stratum corneum (SC) is the outermost part of the epidermis. It is the skin barrier to protect underlying tissue from infection, dehydration, chemicals, and mechanical stress. The SC consists of three basic components which are corneocytes, corneodesmosomes and intercellular lipids (figure 2). A brick-and-mortar-like structure model may be used to describe the structure of skin barrier. Corneocytes “bricks” are nonviable keratinocytes, occupy most of the volume of the SC wall. Corneodesmosomes are proteinaceous rivets holding corneocytes together. Intercellular lipids “mortar” surround corneocytes “bricks”. The main components of Intercellular lipids include around ceramides 50%, cholesterols 25% and fatty acid 10-20% by mass, respectively (1,2,3).
Figure 2. Schematic of the stratum corneum (SC).
The functions of ceramides include decreasing of skin barrier transepidermal water loss (TEWL), increasing of skin barrier water content and decreasing of skin scalines (4,5,6).
Healthy skin barrier helps to keep the skin hydrated and prevent water loss and protect the skin from damage. Ceramides help to support the skin barrier’s health. Rough skin is often because of a loss of ceramides, which can also cause skin dryness, itching, flaking, peeling, and scaling (figure 3).
Figure 3. Schematics of the stratum corneum in healthy skin (left) and rough skin (right).
Ceramides help to supporting the skin’s natural barrier, reduce dryness in the skin, soothe angry or irritated skin. Thus, ceramides skin products are considered good for sensitive skin. Using ceramides based skincare products, such as Tribless® Advanced Ceramide + Hexapeptide Capsules, may help replace intercellular lipids of SC which have been lost due to chemicals, environmental factors, aging, and skin damage caused by certain skin conditions.
Tribless® Advanced Ceramide + Hexapeptide Capsules is rich in Ceramide NG, Ceramide NP, Ceramide AP, Phytosphingosine and Hexapeptide. Ceramide NG, Ceramide NP, Ceramide AP help to repair the skin barrier function, improve skin hydration. Phytosphingosine reduces the signs of acne, reduces redness and inflamed skin. Palmitoyl Hexapeptide-12 stimulates elastin synthesis, increases the elasticity of skin, and imparts skin firming effect.
References:
1. Schaefer H, Redelmeier TE. Skin Barrier: Principles of Percutaneous Absorption. Karger: Basel, 1996:310.
2. Wertz PW, van den Bergh B. The physical, chemical and functional properties of lipids in the skin and other biological barriers. Chem Phys Lipids 1998; 91:85–96.
3. Elias PM. Epidermal barrier function: intercellular lamellar lipid structures, origin, composition and metabolism. J Control Release 1991; 15:199–208.
4. Yang L, Mao-Quiang M, Taljebini M, Elias PM, Feingold KR. Topical stratum corneum lipids accelerate barrier repair after tape stripping, solvent treatment and some but not all types of detergent treatment. British Journal of Dermatology 1995; 133:679–685.
5. Mao-Quiang M, Brown BE, Wu-Pong S, Feingold KR. Exogenous nonphysiologic vs physiologic lipids—divergent mechanisms for correction of permeability barrier dysfunction. Archives of Dermatology 1995; 131:809–816.
6. Mao-Quiang M, Feingold KR, Thornfeldt CR, Elias PM. Optimization of Physiological Lipid Mixtures for Barrier Repair. Journal of Investigative Dermatology 1996; 106:1096–1101.
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