TEWL: Transepidermal Water Loss Defined

TEWL: Transepidermal Water Loss Defined

It’s nearly impossible to talk about skincare without talking about hydration. No matter what kind of skin issue you’re experiencing, it’s very likely that one of the recommended solutions will be to pump up your hydration levels. Just think about it—acne, dry skin, and so much more can be much improved by adding a little boost of hydration.

On the flip side, a lack of hydration may cause just as many issues. There’s a reason your skin might end up looking a little duller than usual after a long night out—when you’re dehydrated after a night of drinking, your skin feels the effects. The same goes for any form of dehydration, really.

Well, it turns out that water loss can occur for any number of reasons. We can’t always blame dehydration on a few too many drinks or a long day of sweating in the sun. Something called transepidermal water loss (TEWL) may play a huge role in the dehydration of the skin.

If you’ve never heard this term before, don’t stress out—it’s not the most common topic of discussion in most circles. Nevertheless, TEWL is an important subject to discuss, especially when it comes to skincare. By understanding the ins and outs of TEWL, you’ll know exactly how to give your skin the care and hydration it needs.

So, read on for a comprehensive rundown of all the facts you should know about TEWL. There’s a lot in store, so let’s get going.

What Is Transepidermal Water Loss? 

Transepidermal water loss, which we’ll just call TEWL, is quite simple. Basically, it is the term used to describe what happens when water passes from the dermis through the epidermis, eventually evaporating from the surface of the skin. Hence: transepidermal.

(Just in case you’ve blocked out all memories of your high school biology class, here’s a quick refresher. The dermis is the layer of skin directly beneath the epidermis, which is the top layer—the one we can touch and see).

TEWL is a normal bodily process, and our bodies regulate it on their own. However, certain external factors may expedite or aggravate TEWL. These circumstances include injury and low-humidity weather (think cold, wintery days that dry out your skin). Even certain topical skincare products may intensify TEWL.

In general, low levels of TEWL are preferable for skincare. High levels of TEWL, on the other hand, may indicate that your skin is overly dry and dehydrated. So, in the next section, we’ll delve into our best tips for ensuring that your skin is getting all the moisture it needs.

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How to Regulate TEWL 

If you’ve made it this far, you probably have one question on your mind—how should I deal with TEWL? What do I need to do about it?

Well, as we’ve already mentioned, TEWL is a self-regulated process. In other words, your body is usually able to keep TEWL in check. However, when certain aggravating circumstances come up, you’re going to want to know how to minimize the damage. So, we’ve put together a short list of the best ways to be sure that your moisture and hydration levels stay high and your skin stays healthy.

So, take a look at this guide:

Protect Your Skin from Harsh Conditions 

As you now know, one of the factors that can intensify TEWL is climates of low humidity. So, when the winter rolls around and the air turns dry, your skin may begin to lose a lot of hydration. 

One of the best ways to protect against this loss of moisture is to literally protect your skin. In other words, if you know you’re going to be spending time outdoors during those colder months, be sure to bundle up. Throw on gloves, a scarf, a hat—whatever it takes to hold in that moisture.

In addition, you may want to limit the time you spend in harsh, cold environments. If possible, try to stay inside when the humidity gets really low. 

Watch Your Exfoliation 

Next up is a fairly simple one—limit how often you exfoliate. Although exfoliation is certainly necessary for healthy skin, it has the potential to be quite damaging if you do it too often. With that in mind, be sure to pay attention to your exfoliation schedule, as well as how your skin reacts to exfoliation.

Beyond frequency alone, there’s another factor to consider when setting your routine—the type of exfoliation you choose. Generally speaking, there are two main types of exfoliation: mechanical and chemical.

Mechanical exfoliation entails using some type of scrubber, like a sponge, washcloth, or brush to cleanse the face and remove dead skin cells. Most of the time, mechanical exfoliation is the best choice for people with oily skin.

On the other hand, you’ve got chemical exfoliation. This process is gentler—it involves using a product with either natural or man-made ingredients that gently dissolve dead skin cells. As to be expected, this type of exfoliation is best for people with sensitive skin, acne-prone skin, or combination skin.

Sometimes, it takes a bit of time and effort to figure out the best products and ingredients to use for your exfoliation routine. Likewise, it may be difficult to get your exfoliation schedule exactly right. However, once you do, your skin will thank you, and you’ll find that you’re able to keep TEWL in check.

Choose the Right Ingredients 

Finally, let’s discuss one of the most important factors to consider in all of this—the skincare ingredients you choose to use. Certain ingredients are ideal for strengthening your skin’s natural moisture barrier and reducing the drying impact of TEWL. 

For your convenience, we’ve compiled a short list of some of the best, all-natural ingredients for keeping your skin moisturized and hydrated at all times. Take a look:


  • Hyaluronic acid. This popular ingredient is a major hydrator. Basically, hyaluronic acid locks in water molecules, holding them onto the surface of your skin. So, when it comes to TEWL, hyaluronic acid greatly reduces water loss. It helps you hold onto all that moisture by decreasing the rate of water evaporation.

  • Aloe vera. This ingredient is a natural gel that comes from the leaves of the aloe vera plant. It brings countless skin benefits to the table, including moisturization. Like hyaluronic acid, aloe vera is ideal for locking in water molecules, therefore reducing TEWL. 

  • Shea butter. Finally, shea butter is an excellent ingredient for improving the skin’s natural moisture barrier. It softens and smooths the skin while strengthening that barrier, helping you hold onto moisture. It’s a perfect ingredient for fighting dry skin and TEWL.

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    Wrapping It Up 

    Well, at this point, you should be a real expert on TEWL. Hopefully, we’ve provided some effective resources for keeping your skin feeling soft, hydrated, and moisturized. As the colder seasons get closer and closer, it’s more important than ever to remember these tips.

    If you’re looking to treat yourself to an ultra-moisturizing face mask, be sure to check out our Vitamin C Clay Mask. With tons of superfood ingredients (including aloe vera), it will certainly keep those hydration levels high. 


    Transepidermal Water Loss - an overview | Science Direct

    7 Surprising Benefits of Hyaluronic Acid | Healthline

    Aloe Vera - Health Benefits, Common Uses, Side Effects, and Risks | WebMD

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