What is Trans-epidermal water loss (TEWL)

Trans-epidermal water loss (TEWL) is a natural process in which water evaporates from the skin's surface through the outermost layer of the skin, known as the stratum corneum. TEWL is influenced by various factors including environmental conditions, skin hydration levels, and the integrity of the skin barrier.

Here's a breakdown of TEWL and its significance:

  1. Skin Barrier Function: The skin's outermost layer, the stratum corneum, acts as a barrier that regulates the movement of water and other substances in and out of the skin. It helps maintain skin hydration by preventing excessive water loss and protecting against external irritants, pathogens, and environmental stressors.

  2. Natural Process: TEWL is a normal physiological process that occurs continuously as part of the skin's regulatory mechanisms. It helps regulate body temperature, remove waste products, and maintain overall skin health

  3. Factors Influencing TEWL: TEWL can be influenced by various internal and external factors. Internal factors include age, skin type, skin conditions, and overall health, while external factors include environmental humidity, temperature, exposure to harsh chemicals, and certain skincare practices.

  4. Effects of Excessive TEWL: Excessive TEWL can lead to dehydration and compromise the skin's barrier function. It can result in dryness, flakiness, roughness, and increased susceptibility to irritation, inflammation, and microbial infections. Certain skin conditions such as eczema, psoriasis, and atopic dermatitis are associated with impaired skin barrier function and increased TEWL.

  5. Prevention and Management: To prevent excessive TEWL and maintain optimal skin hydration, it's important to practice good skincare habits such as using gentle cleansers, avoiding harsh chemicals and hot water, moisturising regularly, and protecting the skin from environmental stressors with sunscreen and protective clothing. 

In summary, trans-epidermal water loss (TEWL) is a natural process through which water evaporates from the skin's surface. Maintaining optimal skin hydration and barrier function is essential for overall skin health and function. Understanding the factors that influence TEWL and adopting proper skincare practices can help maintain healthy, hydrated, and resilient skin.