Transepidermal water loss (TEWL)

Transepidermal water loss (TEWL) refers to the natural process by which water passes from inside the body through the outer skin layer and evaporates into the environment. It helps maintain skin’s hydration and barrier function. When the skin is healthy and intact, TEWL is controlled, preventing excessive water loss. Factors like skin damage, dryness, or environmental conditions can increase TEWL, leading to dehydration, dryness, or irritation. Monitoring TEWL is important for understanding skin health and conditions such as eczema or psoriasis, and for developing skincare products that help strengthen the skin’s barrier.