TEWL (Transepidermal Water Loss)

Why It Matters

When you’re doing everything right — drinking water, layering hydrating products, using a gentle cleanser — but your skin still feels parched? TEWL might be the missing link. It explains why hydration doesn’t always stick and why skin that looks smooth in the morning can feel rough by night.


By understanding transepidermal water loss, you’ll start to see why protecting your skin’s moisture barrier is just as important as hydrating. Glow routines that overlook this often lead to dehydrated skin — where your skin lacks water, not oil, and struggles to retain that lit-from-within look.

GLOW TIP Seal in your hydrating layers with an occlusive moisturizer to help reduce transepidermal water loss— especially overnight when skin is most vulnerable to moisture escape.


Why We Love It For Glow

When it comes to glowing skin, what you keep in is just as important as what you put on. TEWL is the quiet culprit behind sudden dullness, tightness, and that frustrating feeling when your skincare stops hitting the same. By understanding what contributes to water escaping from your skin (think: compromised barrier, dry air, over-exfoliation), you can start choosing formulas and rituals that truly seal the glow in.

TEWL is also one of the most important concepts to know if you’re prone to dehydrated skin. Supporting your barrier, using occlusives when needed, and layering hydrating ingredients like hyaluronic acid and glycerin, all help minimize TEWL and restore that supple, light-reflective finish.


Reach for Avène Cicalfate+ Restorative Protective Cream — a cult-favorite occlusive that helps visibly comfort skin while locking in hydration.


FAQ

How do I know if I’m experiencing TEWL?

Signs of TEWL often show up as skin that feels persistently tight, flaky or irritated — even after moisturizing. If your skincare seems to “disappear” quickly or you constantly need to reapply products, your barrier might be letting hydration escape.

Can I completely stop TEWL?

Not entirely — a small amount is natural. But with the right products and habits, you can dramatically minimize excessive loss. Look for ingredients that seal in moisture (like petrolatum or squalane) and layer them over humectants for best results.

Does TEWL affect all skin types the same way?

Not quite. While everyone experiences some level of water loss, those with dehydrated skin, compromised barriers, or exposure to harsh environments (like dry air or over-exfoliation) tend to be more impacted. Even oily skin can experience TEWL beneath the surface.