Transepidermal water loss and skin barrier health.

Your skin’s primary role is to function as a barrier, protecting you from environmental stressors while keeping essential moisture inside. One of the most important markers of skin barrier health is something called transepidermal water loss, or TEWL. It is not often discussed outside of dermatology, but understanding TEWL can help you make smarter choices about your skincare, especially if you have dry, sensitised or acne-prone skin.

What is TEWL?

TEWL refers to the amount of water that evaporates through the outermost layer of the skin, the stratum corneum. A healthy skin barrier reduces this water loss significantly, keeping skin hydrated, soft and resilient. When the barrier is weakened by harsh products, over-exfoliation, weather or inflammation, TEWL increases. The result is dryness, flaking and a reduced ability to defend against microbes or allergens (Elias, 2005). A compromised skin barrier makes the skin more vulnerable to sensitivity and breakouts (Yamamoto, Takenouchi and Ito, 1995).

Commonly used acne actives, such as benzoyl peroxide and topical retinoids, can compromise the stratum corneum and elevate TEWL, reinforcing the value of pairing them with barrier-supportive moisturisers (Sukanjanapong et al., 2024). Monitoring and managing TEWL is an objective way to assess whether skincare is helping or harming the skin barrier.

How do skincare products affect TEWL?

It is important to remember that not all moisturisers are created equal. Just because a product makes your skin feel hydrated does not mean it is helping to protect your skin barrier or reduce TEWL. For true barrier support, look for ingredients like glycerin, panthenol, niacinamide and Marula oil. These ingredients do more than just feel good on the skin; they help your skin hold on to water and strengthen its natural defences (Lodén, 2003).

Upenya Moisturising Gel and TEWL

Upenya’s Moisturising Gel has been instrumentally evaluated over 28 days and shown to produce a statistically significant reduction in TEWL (p < 0.05). The skin was demonstrably better at holding onto moisture, an essential sign of improved barrier support.

Ingredients in Upenya Moisturising Gel that support barrier health include:

·      Niacinamide:

To visibly calm the look of the skin and support ceramide production.

·      Panthenol and Glycerin:

To enhance water retention.

·      Inulin and Aloe Ferox Leaf Extract

To support the skin microbiome.

·      Marula Oil

To help support the skin’s lipid matrix.

The gel has good skin compatibility and is well tolerated, making it suitable for sensitive or compromised skin, ideal for teenagers dealing with dryness, oiliness or mild breakouts.

How to support your skin barrier health and reduce TEWL

You do not need dozens of products to protect your barrier. Focus on basic, evidence-based strategies:

·      Cleanse gently. Avoid stripping foams or frequent exfoliation.

·     Moisturise consistently. Use barrier-supportive ingredients.

·     Avoid overuse of actives. Especially acids and alcohol-based products.

·     Use microbiome-friendly formulations. These support long-term

balance.

·     Protect against cold, dry environments. External stressors can worsen

TEWL.

TEWL is a powerful, science-based measure of skin health, and reducing it is vital in keeping skin hydrated, comfortable and resilient. Products like Upenya’s Moisturising Gel not only make the skin feel more comfortable, but also support the skin’s ability to hold onto moisture and function as a strong, healthy barrier.

References

Elias, P.M. (2005) ‘Stratum corneum defensive functions: an integrated view’, Journal of Investigative Dermatology, 125(2), pp. 183–200. Available at: https://doi.org/10.1111/j.0022-202X.2005.23668.x (Accessed: 11 June 2026).

Lodén, M. (2003) ‘Role of topical emollients and moisturizers in the treatment of dry skin barrier disorders’, American Journal of Clinical Dermatology, 4(11), pp. 771–788. Available at: https://doi.org/10.2165/00128071-200304110-00005 (Accessed: 11 June 2026).

Sukanjanapong, S. et al. (2024) ‘Skin barrier parameters in acne patients compared with healthy controls’, Clinical, Cosmetic and Investigational Dermatology, 17, pp. 1899–1908. Available at: https://doi.org/10.2147/CCID.S476004 (Accessed: 11 June 2026).

Yamamoto, A., Takenouchi, K. and Ito, M. (1995) ‘Impaired water barrier function in acne vulgaris’, Archives of Dermatological Research, 287(2), pp. 214–218. Available at: https://doi.org/10.1007/BF01262335 (Accessed: 11 June 2026).