What Is Transepidermal Water Loss and How Do I Prevent It?

What Is Transepidermal Water Loss and How Do I Prevent It?

Transepidermal water loss (TEWL) refers to the process where water passes from the deeper layers of the skin (dermis) to the surface and then evaporates into the environment. It’s a natural and ongoing process, but when TEWL becomes excessive, it leads to dehydration, dryness, irritation, and a compromised skin barrier. Preventing excessive TEWL is essential for maintaining healthy, supple, and resilient skin.

What Causes Transepidermal Water Loss?

TEWL happens when the skin barrier—especially the outermost layer known as the stratum corneum—is compromised or not functioning optimally. Several factors can increase TEWL:

• Harsh cleansers or over-exfoliation that strip natural oils

• Cold, dry, or windy weather

• Low humidity environments (e.g., air-conditioned rooms)

• Hot showers or long baths

• Frequent use of alcohol-based products

• Skin conditions like eczema or psoriasis

• A damaged skin barrier from overusing actives like retinol or acids

Signs of Excessive TEWL

When your skin loses too much water, you may experience:

• Dryness or tightness

• Flaky or rough patches

• Sensitivity or redness

• Dull or tired-looking skin

• An increase in fine lines or irritation

How to Prevent and Reduce TEWL

1. Strengthen the Skin Barrier

A healthy skin barrier is your best defense against TEWL. Support it by:

• Using gentle, non-stripping cleansers

• Avoiding products with alcohol, sulfates, or harsh surfactants

• Limiting exfoliation to 1–2 times per week

2. Hydrate, Then Seal

Use products that attract and retain moisture, followed by ones that seal it in:

• Humectants (like hyaluronic acid, glycerin, and aloe vera): These draw water into the skin.

• Emollients (like squalane, ceramides, and fatty acids): These fill in gaps between skin cells and smooth the skin.

• Occlusives (like petrolatum, shea butter, and dimethicone): These form a protective barrier that locks in moisture and prevents evaporation.

A good skincare routine to combat TEWL includes layering: apply a humectant serum first, followed by a moisturizer rich in emollients and an occlusive, if needed.

3. Avoid Hot Water

Very hot showers or face washing can strip natural oils and worsen TEWL. Use lukewarm water instead and pat skin dry gently with a soft towel.

4. Use a Humidifier

If you spend time in dry indoor environments (especially in winter or under air conditioning), a humidifier can help maintain moisture levels in the air, reducing evaporation from your skin.

5. Apply Moisturizer Immediately After Cleansing

To trap water in the skin, apply moisturizer while your skin is still slightly damp after washing.

6. Sunscreen Is Essential

Sun damage weakens the skin barrier and increases TEWL. Apply a broad-spectrum SPF 30+ daily to protect your skin from UV exposure and moisture loss.

Final Thoughts

Transepidermal water loss is a normal process, but when it becomes excessive, it compromises skin health. By focusing on barrier protection, hydration, and gentle skincare practices, you can prevent TEWL and maintain plump, healthy, and radiant skin. Consistency, along with the right products and environment, is key to keeping your skin’s moisture where it belongs—inside.