Transepidermal Water Loss (TEWL)

What is TEWL?

Transepidermal water loss (TEWL) is the natural evaporation of water from the skin into the air. While it’s a normal skin function, excessive TEWL can cause dryness, irritation, and a weakened skin barrier.

Why It Matters

Skin dehydration – High water loss causes the skin to lose moisture, leading to a tight, rough, or flaky texture.

Barrier damage – Excessive water loss weakens the skin’s protective layer, increasing sensitivity and inflammation.

Premature ageing – A compromised barrier makes the skin more susceptible to fine lines and environmental damage.

How Skincare Can Help

Skincare products can strengthen the skin barrier and lock in moisture. Ingredients such as ceramides, glycerin, hyaluronic acid, and fatty acids help retain water and repair the skin’s natural defenses. Using moisturisers with both humectants (to draw in moisture) and occlusives (to seal it in) is essential.

How to Avoid It

High TEWL is common in conditions such as eczema, psoriasis, and after excessive use of exfoliating acids or retinoids. When the skin barrier is damaged, harsh products can worsen the issue. Using gentle, barrier-supporting skincare is essential in these cases.