To understand what Transepidermal Water Loss really means, we need to have some knowledge of the skin’s main functions. The skin’s primary functions are to serve as a barrier to the entry of microbes and viruses and to prevent water and extracellular fluid loss. Acidic secretions from the skin glands also retard the growth of fungi. Melanocytes form a second barrier: protection from the damaging effects of ultraviolet radiation. When a microbe penetrates the skin (or when the skin is broken by a cut) the inflammatory response occurs.
THE SKIN IS DIVIDED INTO THREE LAYERS
- The Epidermis outer and top layer.
- The Dermis deeper layer.
- The Hypodermis subcutaneous tissues.
THE SKIN FORMS THREE TYPES OF BARRIERS
1. Chemical Barrier – Includes skin secretions and melanin. The skin’s surface is covered with bacteria (skin microbiome) the low pH of skin secretions known as the Acid Mantle decreases their multiplication. Many bacteria are killed by anti-bacterial substances in the sebum. Skin cells also secrete a natural anti-biotic known as ‘human defensin’. Melanin provides a chemical pigment shield to prevent UV damage to viable skin cells. Keratin – is a protein found in skin, hair and nails; it prevents both the loss of body fluid through the skin and entry or excessive water into the body.
2. Physical Barrier – Is offered by the continuity of the skin and the hardness of its keratinised cells. The waterproofing of the glycolipids of water-soluble substances between cells prevents both water loss from and entry into the body through the skin. Substances that do penetrate the skin in limited amounts (here are some examples):
- Lipid-soluble substances such as oxygen, carbon dioxide, fat-soluble Vitamins A, D, E, and K, steroids and some bio-active botanical extracts.
- Oleoresins of certain plants (poison Ivy).
- Organic Solvents such as acetone, dry cleaning fluid, and paint thinner (these dissolve the cell’s lipids).
3. Biological Barriers – Langerhans cells in the epidermis and macrophages in the dermis. Langerhans cells – are active elements of the immune system that protect the Dermis against foreign substances (antigens). Macrophages – are the second line of defence and kill viruses and bacteria that have managed to penetrate the Epidermis.
An aqueous film that covers the Epidermis is known as the Acid Mantle It comprises the:
- Secretions from tour sweat and sebaceous glands.
- Peptides are derived from the breakdown of our dead skin cells known as corneocytes.
- Epidermal lipids provide a protective film comprised of sebum and the epidermal lipids (upper film); underneath (lower film) is the natural moisturising factor (NMF), which is comprised of water-based molecules present on the epidermal surface (the top layer of your skin.
- Up to 15% of the Stratum Corneum (outermost layer of the skin) consists of water. When this drops to below 10% your skin starts to feel dry and flaky. As we age the skin naturally becomes drier.
How To Prevent Transepidermal Water Loss
The Skin is not a completely impermeable barrier, a certain amount of water continuously diffuses into the environment. This is the process known as Transepidermal Water Loss (TEWL). It is defined as “passive water loss through an intact stratum corneum” (excluding active perspiration through sweat glands and hair follicles) Increased TEWL is due to an impaired barrier function usually related to the hydration of the stratum corneum. These two parameters are used for the assessment of the skin’s barrier function and its general condition (health).
The optimal water content of a healthy stratum corneum is 13-20%, preventing excessive TEWL is achieved by maintaining proper hydration of the skin.
ENVIRONMENTAL AGGRESSORS – Wind, cold, and humidity cause dehydration, symptoms of an impaired skin barrier include:
- Flaking: A typical sign of dehydrated skin.
- Tightness: Is often associated with dry skin.
- Redness: Due to the barrier being unable to protect against irritants causing Inflammation.
- Itchiness: The damaged barrier can affect nerve endings which leads to itching, when the skin is scratched to relieve the itching, the barrier function is injured causing inflammation and redness.
What are Emollients, Occlusives and Humectants?
Moisturizers Explained – Depending on the time of the year, your current skin condition and/or issues, and your current skin state, you may need to include one, two or all three types of moisturizers in your self-care ritual
EMOLLIENT – An emollient is an oily substance that fills in the spaces between dead skin cells, thus creating a smooth skin surface. An emollient is a film-forming substance that makes the skin feel and look smooth. While an emollient will provide some occlusive effects, the primary function is to help soften the skin. Emollient ingredients help to repair the skin barrier function. The skin barrier is composed of dead skin cells held together by a lipid matrix. Without these essential lipids, the barrier is weakened. A weak or damaged barrier leads to transepidermal water loss (TEWL). Some examples include:
- Plant Butter
- Botanical Oils
- Fatty Acids
Topical Application of Fatty Acids – Have a number of positive effects on the skin, the most important being, boosting lipid content and the repair of the skin’s barrier function. This helps protect delicate skin, improves moisture levels, and helps the skin retain its own moisture which all leads to improved softness and elasticity. Omegas are particularly beneficial to dry skin, conditions such as eczema and extreme weather conditions, such as cold and wind, both of which can strip away at the skin’s protective lipid barrier.
Ceramide NP – Plays an important role in having a healthy skin barrier and keeping the skin hydrated, functioning as the main storage area for linoleic acid which is a critical fatty acid for a healthy skin barrier.
Omegas 3 and 6 – These are building blocks of healthy cell membranes. These are polyunsaturated fats and help the skin’s natural oil barrier – this is critical in keeping the skin hydrated, ‘plump’ and preventing water loss.
OCCLUSIVES – Create a thin film over the skin, helping to create a barrier against water loss, preventing the skin from losing moisture. They don’t increase the moisture levels of the skin but can help prevent water reserves from being drained by external stressors.
- Avocado Oil – Prevents the evaporation of water from the surface of the skin, and contains Lecithins which help to prevent moisture loss.
- Polyglyceryl-3 Beeswax– [Cera Bellina] has had its fatty acids converted into polyglycerol esters, this means that this type of beeswax can mix with water better. Provides a physical barrier, sealing moisture into the tissues whilst preventing water loss.
- Jojoba Oil – Technically although resembling an oil it is in fact a wax. It provides a light film on the skin that maintains and attracts moisture.
- Babassu Butter – Moisturizes dry skin, reduces trans-epidermal water loss, maintains hydration, and creates occlusion it provides immediate coolness and softness.
- Squalene – [From Olives] hydrating properties and maintains our skin’s own moisture barrier, absorbs well into the skin and helps to replenish lipids, non-comedogenic and has been shown to have anti-inflammatory and microbiome-nourishing properties.
HUMECTANTS – Have the ability to pull water from the dermis to the epidermis and stratum corneum. In addition, humectants can draw water vapour from the air to help moisturize the skin if the humidity is over 50%. These are water-rich, they mimic the skin’s sweat and work by hydrating the skin. They have been specifically designed to prevent water loss and protect the stratum corneum, the outer layer of skin from becoming dry and parched. Some humectants are capable of holding up to 1000 times their own weight in water, acting as moisturizers for the skin:
- Aloe – Penetrates skin deeply and quickly, hydrating at the surface and at the lower levels. Due to its gentle properties, aloe is great for hydrating dry skin that is also sensitive.
- Honey – With the ability to hold onto water, hydrating without creating an oily feel. It’s also a natural source of alpha hydroxy acids, which encourage exfoliation. This makes it even easier for the skin to absorb the moisturising elements.
- Hyaluronic Acid – A natural molecule present throughout the body that helps hydrate and cushion joints, eyeballs, and skin. It has a natural ability to hold onto water, and seems able to adjust according to humidity levels, helping your skin cope with even dry climates. Antioxidant properties and an impressive ability to hold up to 1000 times its weight in water make this a popular addition to many skincare products.
- Glycerin [Vegetable] – It occurs naturally in every living cell so it’s easily absorbed by the skin. It holds water really well and it works by finding an equilibrium between the water content in the air and in the skin. Along with the benefits of deep hydration, the texture of glycerin makes it perfect for skin care because it glides on smoothly and evenly. It is derived from plant-based oils and helps keep the skin soft, as it continues to work even after it has been rinsed off. Glycerol is colourless, odourless and very gentle on the skin, making it safe for sensitive skin.
- Lecithin – [from soya beans or sunflower] Hydrophilic ingredient – It attracts water to the skin, working to prevent moisture loss from deep within the skin tissues.
- Seaweed and Algae – Creating a moist film over the surface of the skin, helping to retain water in the skin’s upper layers.
STEPS YOU CAN TAKE TO MAINTAIN HYDRATED SKIN
- Apply a Face oil/serum, or moisturiser to protect from transepidermal water loss.
- Avoid exposure to dry air, where possible!
- Avoid prolonged contact with hot or chlorinated water.
- Use a gentle Cleansing Oil or balm instead of soap.
- Avoid using skin care products that contain alcohol.
- Moisturise immediately after a bath, shower or washing your hands and regularly throughout the day, adding moisture to the skin helps to normalise cell turnover and strengthen the skin’s barrier function.
- Use a humidifier.
- Wear a scarf and gloves when going out in cold weather.
FIFTY7KIND formulas are holistically designed to protect and restore skin, improving skin functionality and promoting healthier skin – for an exceptional experience. NADI – Innate Flow Quell Balsam has been specifically formulated to help prevent Transepidermal Water Loss.
- Skin Barrier Support – Phytoceramides, Phospholipids, Acai Sterols, and Unsaponifiables, along with a patented mix of Triglycerides, Wax Esters, Squalane, Sterol Esters, to rebuild the skin’s surface lipids, strategically offering restorative skin barrier support, while calming botanical-synergies comfort stressed and irritated skin.
- The optimal blend of Moisturising Agents – Humectants drawing in moisture, Emollients, softening the skin and Occlusives providing a protective seal on the skin locking in hydration.
- Green-Biotechnology – Innovated with 6 High-Performance Clinically-Proven Actives.
- Multi-Award-Winning – Six International Beauty Shortlist Awards.
Until next time, be human, be kind, be you
BOOK: Modern Cosmetics – Ingredients of Natural Origin A Scientific Review Volume 1 – Dr D Janes & Dr N K Glavac.