Skin Moisture Barrier and Trans-Epidermal Water Loss

Updated: Jul 15, 2021

Did you know that your skin, if laid flat, would take up an area of around 2 square metres? This make skin the largest organ of our body, and an important one at that.

Skin Protective Barrier

Our skin's major function is to create a strong, flexible barrier between what constitutes us and the external environment. Having evolved from simple aquatic organisms, the transition our ancestors made to life on dry land required a waterproof barrier, in order to protect our moisture-rich interior from drying out. This is where the skin comes in: we wouldn’t last a moment without it, which makes it an organ as vital as our heart of lungs.


Dry skin as a result of trans-epidermal water loss
Skin with barrier integrity damaged vs healthy skin

Transepidermal water loss (TEWL) occurs when water from our skin evaporates into the surrounding environment. More water evaporates from skin whose barrier has been compromised. Broken skin barrier and TEWL have been shown to be correlated to skin ageing, more pronounced appearance of fine lines and wrinkles, as well as sensitivity to skin irritation, which studies show to be increased especially in post-menopausal women. High levels of TEWL are also