TEWL: The Hidden Leak in Your Skin Barrier

What Is TEWL?

TEWL stands for Transepidermal Water Loss. It refers to the amount of moisture your skin passively loses into the air every day.

Some water loss is normal — in fact, healthy skin loses around 4–10 g/m² per hour, or roughly 500 mL per day. But when the skin barrier is compromised, TEWL can increase dramatically — up to 30 times higher, according to clinical data (Klotz et al., 2022).

This elevated water loss signals barrier dysfunction — and often, inflammation just beneath the surface.

What Happens When TEWL Is Too High?

When TEWL rises, skin starts to unravel in quiet, uncomfortable ways:

• Dryness and flaking
• Burning or stinging when applying skincare
• Chronic redness or sensitivity
• Flare-ups of rosacea, acne, or perioral dermatitis
• A constant feeling of “tightness,” even after moisturising

In my practice, high TEWL is one of the earliest signs that a client’s skin is not safe — it’s in a state of overexposure.

What Causes TEWL to Increase?

Many common skincare habits (even gentle ones) can increase TEWL:

• Over-cleansing with foaming agents or micellar water
• Use of harsh actives (retinoids, exfoliating acids)
• Sun and wind exposure
• Stress-induced cortisol spikes
• Inflammatory skin conditions (e.g. eczema, rosacea)
• Long-term barrier trauma from stripping facials or too many products

Even well-meaning skincare routines can trigger the spiral — especially when the skin is already vulnerable.

The Science Behind TEWL

A growing body of research confirms that TEWL is more than a number — it’s a clinical signal of how well the skin is functioning.

• A 2021 JBI review identified TEWL as a central indicator of barrier health, especially in treating sensitive and inflamed skin.
• A 2024 Japanese clinical study found that krill oil supplementation significantly reduced TEWL, improving skin elasticity and water retention in healthy adults.
• Infant dermatology research consistently shows that trilipid barrier creams (containing ceramides, cholesterol, and fatty acids) reduce TEWL far more effectively than paraffin-based emollients.

Together, this science echoes what corneotherapists have always known:
Skin heals when the barrier is supported.

How We Treat TEWL at Corneotherapy NZ

In our practice, we use TEWL not just as a concept — but as a compass for your skin’s journey.

Step 1: Understand the cause

We explore your skin history, environment, stress load, and current routine.

Step 2: Gently calm the leak

We reduce exfoliation, avoid stripping actives, and apply trilipid-based, inflammation-aware topicals to support restoration.

Step 3: Track and nurture

Over time, we observe changes in barrier resilience, water retention, and sensitivity. You’ll feel the difference — and your skin will show it.

Why TEWL Matters More Than Your Serum Label

You can buy an expensive hyaluronic acid serum.
But if your skin barrier is leaking, it won’t matter.

That’s why I always ask:
Is your skin holding onto what you give it?
Or is it silently overwhelmed?

In corneotherapy, we stop chasing actives — and start rebuilding the skin’s ability to hold, protect, and repair. That’s how we restore true calm.

Final Thoughts:

Your skin isn’t dry because it’s dehydrated.
It’s dehydrated because it’s defenceless.

TEWL gives us the first clue.
And corneotherapy offers a way back. Begin your healing Journey with us to feel confident in your skin like never before.