Why transepidermal water loss matters for skin barrier health.

Photo by @simoneschoemanprinsloo

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's not often discussed outside of dermatology, but understanding TEWL can help you make smarter choices about your skincare, especially if you have dry, irritated, 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 an impaired ability to defend against microbes or allergens [1]. A compromised skin barrier makes the skin more vulnerable to irritation, sensitivity, and breakouts [2].Commonly used acne treatments (e.g. benzoyl peroxide, topical retinoids) can compromise the stratum corneum and elevate TEWL, reinforcing the need to pair them with barrier-supportive moisturizers [3]. 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 [4]. So, when you are choosing a moisturiser, don’t just look for a lovely texture, pleasing scent or instant results. Focus on what supports your skin’s health overall.

Ingredients like glycerin, panthenol, niacinamide, and Marula oil reduce TEWL by improving the skin’s natural water retention capacity and lipid structure [4].

Upenya Moisturising Gel and TEWL

Upenya's Moisturising Gel has been clinically evaluated and shown to produce a statistically significant reduction in TEWL after just four weeks of use (p < 0.05). The skin was demonstrably better at holding onto moisture - an essential sign of improved barrier health.

Ingredients in Upenya Moisturising Gel that assists with barrier health are:

• Niacinamide to visibly calm 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 restore the skin’s lipid matrix.

The gel is non-irritating and suitable for sensitive or compromised skin - ideal for teenagers dealing with dryness, oiliness, or mild breakouts.

How to support your barrier and reduce TEWL

You don’t need dozens of products to protect your barrier. Focus on basic evidence-based strategies:

1. Cleanse gently – Avoid stripping foams or frequent exfoliation.

2. Moisturise consistently – Use barrier-supportive ingredients.

3. Avoid overuse of actives – Especially acids and alcohol-based treatments.

4. Use microbiome-friendly formulations – These can support long-term balance.

5. 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 to 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

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

2. Yamamoto, A., Takenouchi, K. & Ito, M. Impaired water barrier function in acne vulgaris. Arch Dermatol Res 287, 214–218 (1995). https://doi.org/10.1007/BF01262335

3. Sukanjanapong, S., Limpawattana, P., Kamanamool, N., Pichaiyongwongdee, S., & Kulthanan, K. (2024). Skin barrier parameters in acne patients compared with healthy controls. Clinical, Cosmetic and Investigational Dermatology, 17, 1899–1908.  https://doi.org/10.2147/CCID.S476004

4. 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. https://doi.org/10.2165/00128071-200304110-00005