Transepidermal Water Loss

Transepidermal water loss (TEWL) refers to the process by which water passes from inside the body through the epidermis (the outermost layer of the skin) to the surrounding environment. It's a natural phenomenon that occurs continuously as part of the skin's normal functions. TEWL plays a crucial role in maintaining the skin's hydration levels and overall barrier function.
The skin acts as a protective barrier, preventing excessive water loss and guarding against harmful substances and microorganisms. The outermost layer of the epidermis, known as the stratum corneum, is particularly important in regulating TEWL. It consists of dead skin cells embedded in a lipid matrix, forming a barrier that helps to retain moisture within the skin and prevent dehydration.
Various factors can affect TEWL, including environmental conditions (such as temperature, humidity, and wind), skin integrity (e.g., damage from injuries or skin conditions), and the use of skincare products (such as moisturizers and barrier creams). High levels of TEWL can contribute to dry skin, leading to discomfort, irritation, and increased susceptibility to certain skin problems.
Measurement of TEWL is commonly used in dermatology and skincare research to assess skin barrier function and hydration levels. Techniques such as evaporimetry or conductance measurements are employed to quantify TEWL non-invasively. By understanding TEWL and its influencing factors, skincare professionals can develop effective strategies to maintain skin health and hydration.