
Transepidermal water loss, or TEWL, is a term commonly used in skincare, but many people are unfamiliar with what it actually means and why it is so important for your skin. Here is everything you need to know about transepidermal water loss and its effects, as well as some tips for achieving and maintaining the look and feel of smooth, hydrated skin.
What Is Transepidermal Water Loss?

Circumstances such as injury, low-humidity weather conditions and topically applied products that dry out the skin can impact TEWL.
The skin is comprised of three primary layers: the epidermis, the outermost layer; the dermis or middle layer; and the hypodermis, the undermost layer. When water passes from the dermis through the epidermis and evaporates from the skin’s surface, this is known as transepidermal water loss (International Journal of Pharmaceutics). While TEWL is a process that your skin naturally regulates, certain factors that can damage the skin’s barrier function can also affect TEWL levels. Circumstances such as injury, low-humidity weather conditions and topically applied products that dry out the skin can impact TEWL.
The Importance of Skin Moisturization and Hydration

To achieve this, combine humectant and occlusive skincare ingredients.
Transepidermal water loss can contribute to a variety of dry skin conditions, and although it is a natural process, there are ways that you can help your skin stay moisturized and hydrated. Hydration refers to the water content of the skin, whereas moisturization is the skin’s ability to retain those water molecules. Therefore, your skin needs both elements to maintain desirable levels of TEWL.
To achieve this, combine humectant and occlusive skincare ingredients. Humectants help to draw moisture to the epidermis, either from the air if it is humid enough, or from the underlying dermis in low-humidity conditions. Because water content that is drawn from the dermis can be lost through TEWL, it’s important to combine the use of humectants with occlusives. Together, these ingredients create a reservoir of moisture in the epidermis and act as a barrier on the skin to help prevent TEWL by sealing in that moisture. The occlusive agents simultaneously keep pollutants, toxins and harmful bacteria out (Skin Therapy Letter).
How to Help Keep Skin Moisturized

If you use a night cream that tends to irritate or dry your skin, you might consider switching to a formula such as skinbetter science AlphaRet™ Overnight Cream FACE.
When you experience dry or flaky skin, you can help prevent excess TEWL and protect the skin’s barrier with frequent moisturization using products that contain humectants and occlusives. If you’re not sure which moisturizers are the most appropriate for your skin type or condition, consult your dermatologist for a professional skin evaluation and recommendations for the most effective skincare products and ingredients.
You can also look for moisturizing ingredients in the day and night creams that you apply regularly to help improve the look and feel of your skin. Skinbetter science Daily Treatment Cream EYE, for example, contains a lavish blend of moisturizing ingredients, including glycerin, jojoba esters and niacinamide to provide a smooth, hydrated look and feel to delicate eye area skin.
If you use a night cream that tends to irritate or dry your skin, you might consider switching to a formula such as skinbetter science AlphaRet™ Overnight Cream FACE. This night cream contains a patented blend of a retinoid with an alpha hydroxy acid to help smooth away the appearance of lines and wrinkles with little to no irritation*. In addition, AlphaRet™ contains a hydrating blend of squalane, niacinamide, ceramides and fatty acids to provide deep moisturization.
In Summary
Transepidermal water loss can contribute to a variety of unwanted skin conditions, including a more pronounced appearance of fine lines and wrinkles. For a complete approach to skin anti-aging, use skincare products that contain effective moisturizing ingredients that won’t cause irritation or dryness. This can have a very positive impact on the smooth and radiant look and feel of your complexion.
*Individual results may vary.