The Importance of Transepidermal Water Loss

What is transepidermal water loss?

Transepidermal water loss, otherwise known as TEWL, is a process in which moisture travels through the deeper layers of the skin and evaporates from the stratum corneum, the outermost layer of our skin. Present day research has not definitively defined what exactly a “normal” TEWL looks or feels like; however, studies have demonstrated that increased TEWL can often result in overall dry and/or dehydrated skin while normal or decreased levels of TEWL have been shown to be a marker of a properly functioning skin barrier. 

Maintaining a substantial amount of moisture in the skin is vital to overall function. Common skin conditions such as eczema, psoriasis, atopic dermatitis etc. have been known to involve compromised skin thus allowing excess moisture to release into the surrounding environment. But no need to fear as it is possible to get your skin back on track and moisture packed once again! 

What factors can cause TEWL?

Although TEWL is a naturally occurring process in our body that is completely normal in regards to water content regulation, it can be heightened by certain factors. In order to combat this issue, we first must understand intrinsic or environmental conditions can result in increased TEWL. 

  • Age and sex have not been considered as having a significant effect on TEWL
  • Skin temperature has been cited as critical for maintaining a certain degree of moisture
  • Additionally, humidity of the surrounding environment, sweating, existing skin conditions, and cleansing may potentially decrease the skin's internal moisture content

What is the impact on the skin?

Since TEWL indicates a loss of water in our skin, it can have a profound impact on the overall quality of the skin. Common signs of TEWL include dry, flaky, irritated, dull skin with more noticeable fine lines if the condition is persistent. 

What types of skincare products help with TEWL?

There are many ways to prevent TEWL and also get moisture back into your skin through skincare products.

In terms of ingredients, making sure you have humectant and occlusive ingredients in your moisturizing steps is vital. Humectant products work to draw water from the surrounding environment directly to our skin while occlusive products act as a sealing barrier to make sure that moisture stays within our skin cells while filling in gaps between them. Example of these types of ingredients include allantoin, butylene glycol, hyaluronic acid, squalene, paraffin, and jojoba oil. 

In addition, ensure that your cleanser does not strip your skin and feel overly 'tight' after usage. Usually cleansers are formulated to inhibit the negative effects of harsh surfactants like sodium lauryl sulfate, but always double check and opt for more gentle surfactants such as sodium cocoyl isethionate and rhamnolipids found in our CALM cleansing capsules. 

What else can I do to prevent and treat TEWL?

Since TEWL can be a result of a damaged skin barrier, including probiotics is a must! They are amazing for maintaining the internal skin microbiome which can prevent general skin issues that could lead to TEWL, preventing it from occurring down the line.

Remember that our external environment is constantly changing and TEWL is completely normal for our body to remain as balanced as possible. But when it begins to severely impact our skin, it's important to think about your lifestyle and routine and what you can do to add that kick of moisture back in.