What is Transepidermal Water Loss

Images of women expressing concern about their skin conditions

As a licensed esthetician, I have seen firsthand the impact of transepidermal water loss (TEWL) on the skin's health and appearance. I also experience this myself. 


But what is transepidermal water loss? How does it tie into skin barrier health and why is it so critical for the healthy, glowing, radiant skin you dream of? Let's dive in.

What Is Transepidermal Water Loss

Think of Your Skin As a Grape 

To understand how TEWL affects the appearance of your skin, think of a grape.


When the grape is filled with water, it's plump and bouncy, just like our skin, when it's hydrated. 


But when the grape becomes a raisin, it becomes wrinkly and saggy, just like our skin when it's dry and dehydrated.  


I dunno about you, but I don't want the skin of a raisin, do you?


In a nutshell, TEWL stands for transepidermal water loss, which is the process of water evaporating from our skin's surface. 


This happens through a layer of skin called the stratum corneum, which is also responsible for showing signs of aging on our skin.


When the skin's barrier function is compromised, the skin loses moisture more quickly, leading to dehydrated skin and impaired barrier function. 


Ok, Sonia, but how does this affect how my skin looks?

TEWL: Grapes vs Raisins Infographic - Skin Dehydration

Don't let transepidermal water loss compromise your skin's health!

The Anatomy of Your Skin:

The skin is made up of three primary layers: the epidermis, dermis, and subcutaneous tissue.


TEWL or Transepidermal Water Loss is the amount of water lost from the skin's surface through the stratum corneum, found in the outermost layer of the skin, known as the epidermis. 


Another name for the stratum corneum is the "horny outer layer" Yes, I just heard you giggle.  


This is also the layer of skin we put all the lotions and potions and makeup on. So needless to say, that horny layer can get a real workout most days.

Skin Layers Infographic: Face and Tissue

Why The Stratum Corneum Is Important

The stratum corneum in human skin acts as a barrier, protecting the skin from harmful bacteria, environmental factors, and water loss. 


Think of your skin barrier as your superhero cape. It is responsible for keeping the good stuff in and the bad stuff out. 


Our job as humans is to keep the skin hydrated so that the hardworking stratum corneum can keep the good stuff in and do its job. 


The bad thing is, we tend to aggravate this "horny layer" in an effort to get the smooth skin we all desire. But overdoing can actually cause more TEWL and skin barrier disruption.  We will talk about that in just a sec and give you some skin care tips that will help you maintain a healthy skin barrier.

Woman protecting her skin barrier from sun exposure

What are the symptoms of TEWL?

When the body and skin are suffering from TEWL, it's dry and dehydrated, just like that grape. 


However,  not only will your skin and body feel sensitive and irritated, but it will also look older and weathered. 


Other problems you'll face are things like rashes, redness, fine lines, wrinkles, and texture changes in your skin. 


This is why preventing transepidermal water loss (TEWL) is so important.

Dried fruits assortment and woman with skin condition concerned with her reflection in the mirror

Factors That Affect Your Skin's Barrier Function and Transepidermal Water Loss

Several things control how well your skin can protect itself, certain factors such as how much moisture it can hold, how it regulates body temperature itself, how much oil it produces, and how humid the environment is. 


Wait, say what?


Yes, where you LIVE can have a huge effect on your skin barrier and TEWL levels.


Your Weather & Geographic Location Can Affect TEWL


Low-humidity climates can lead to excessive transepidermal water loss, while high humidity can impair the skin's ability to lose excess water. 


So depending on where you live, there may be some external factors to dry skin conditions you need to account for, than just your skincare routine.


A humidifier, for one, is a great place to start if you live in a dry climate where transepidermal water vapor loss is a problem for many people. I will touch on that at the end.

Woman experiencing dry skin and distress due to extreme weather conditions

What Causes Transepidermal Water Loss?

Several things can harm the skin's ability to protect itself and cause more water to be lost, such as:


For example, using harsh cleansers that are not designed for your skin type or over-exfoliating your skin with too many exfoliants can damage the outermost layer of the skin, making it harder for the skin to retain moisture. 


Similarly, over-stripping the skin's natural oils in your skin can weaken the skin's barrier function and cause more water to evaporate from the skin's surface. 


In low-humidity environments, the air is dry and can cause water to be pulled out of the skin faster, leading to more transepidermal water loss. 


It's important to be mindful of these factors and take steps to protect your skin's barrier function to prevent excessive TEWL.


Atopic dermatitis, a condition that causes dryness and itchy skin, is also associated with a weakened skin barrier


Aging also affects the skin's barrier function, leading to altered skin barrier structure and function. 


Medications like diuretics can also cause TEWL.

Women looking at the mirror, concerned about their damaged skin barrier

How To Prevent & Treat Transepidermal Water Loss

NEWSFLASH: There is no reason we should clean our face like we clean our kitchen. Our skin is never supposed to be "squeaky clean." 


This is why a good cleansing routine with a cleanser (like Japanese Cleansing Oil) will clean the skin but not disrupt the oils of the skin.


Remember to opt for gentle cleansers and limit exfoliation to once or twice a week


If you have very sensitive skin, I even suggest exfoliation 1-2x a month.

 Japanese cleansing oil in hand for gentle and effective cleansing

Lifestyle Habits That Cause TEWL

Using hot water can also strip your skin of its natural oils, leading to dehydration, so it's best to avoid it.


Smoking also causes TEWL, as well as excessive alcohol consumption, and a diet low in essential fatty acids can also contribute to TEWL.  


Who knew, right? 


So the next time you're out on the town, drink extra water to keep hydrated and double up on your moisturizers before bed.

Lifestyle habits to prevent Transepidermal Water Loss (TEWL)

How To Maintain A Healthy Skin Barrier Function

Maintaining a healthy skin barrier is an essential part of achieving healthy, glowing skin.  


Keeping your skin moisturized is rule #1.


Using great moisturizers like Intense Barrier Cream and Water Balm and hydrating serums can also help retain moisture and prevent TEWL from happening. 


Even if you have to reapply throughout the day, it's worth it in the end.


Use a Hydrating Serum


Use a hydrating serum for an extra boost of moisture, like our Water Elixir, especially if you have dehydrated skin. 


Hydrating serums containing nano-ceramides, hyaluronic acid, and glycerin can help retain moisture in the skin and improve the skin's barrier function. 


Applying hydration or serum before moisturizing can also help enhance the absorption of active ingredients. Think of Water Elixir as a skincare boost.


Ingredients That Work to Avoid TEWL


Several skincare ingredients can help prevent TEWL and improve the skin's barrier function while retaining moisture. 


Look for products that have functional levels of ceramides, which are naturally occurring lipids in the skin, that can help the moisture content restore the skin's barrier function and prevent TEWL. 


Facial oils, niacinamide, or vitamin B3, can also help improve the skin's barrier function and retain moisture.


Advanced Ingredients That Can Help With TEWL:


  • Ceramides
  • Dimethicone
  • Glycosphingolipids
  • Niacinamide
  • Amino Acids
  • Superoxide Dismutase
  • Glycerine
  • sodium PCA
  • Butyrospermum Parkii (Shea) Butter
  • Sodium Hyaluronate-Squalene
  • Peptides

Fatty acids, such as linoleic acid and oleic acid, can help repair the skin's barrier function and prevent TEWL. 


Occlusive agents, such as petrolatum and dimethicone, can also create a barrier to prevent TEWL. 


But before your rip me a new asshole for suggesting petrolatum be used on your skin, let's talk about when you would actually use this ingredient.

Sonia Roselli Collection defends against TEWL - woman holding water balm in hand
Sonia Roselli Beauty

Replenish your skin's moisture barrier!

Example of a Severely Damaged Skin Barrier

Burned skin is a perfect example of a severely damaged skin barrier. Petroleum jelly is a commonly used product for burn victims in the medical field.


Why?


Petroleum jelly can help soothe and protect the wounded skin during the wound-healing process. 


Petroleum jelly acts as a tough occlusive barrier, preventing moisture loss and keeping the skin hydrated. 


This can help reduce pain, itching, and scarring associated with burns. The jelly also helps to protect the skin from bacteria and other harmful external factors, reducing the risk of infection. 


Sometimes, depending on the cause and severity of what has caused a damaged skin barrier, depends on the treatment you'll need to use. 


This is why sometimes you'll get a tube of Aquaphor after an intense laser treatment. We want to keep the water in the skin, and some laser treatments remove all the top layers of the skin.

Woman with sunburned skin, an example of a damaged skin barrier caused by excessive sun exposure

How To Prevent Tewl:

Use A Humidifier For A Compromised Skin Barrier & Transepidermal Water Loss

Adding a humidifier to your living space can be a game-changer for your skin's health and preventing TEWL. 


Not only does it make your room feel like a luxurious spa, but it can also help combat dryness and dehydration


By increasing the humidity in the air, a humidifier helps your skin hold more water content, which strengthens your skin barrier.

Woman using a humidifier to prevent TEWL


Great skincare like Sonia Roselli Beauty

We formulate all of our products to help minimize TEWL in your skin, no matter where you live.

Women holding Sonia Roselli skincare products to protect their skin from TEWL
Sonia Roselli Beauty

Prevent TEWL and enjoy a hydrated complexion!

Fun Facts: 5 Transepidermal Water Loss Measurements (TEWL)


Now let's get all sciencey to bring it all home.


Did you know there are devices that can take TEWL measurements and can provide insight into the skin's skin hydration, levels, and barrier function? Groovy, right?


Several devices can measure TEWL levels, including the Tewameter, Vapometer, and Skicon. 


Understanding TEWL measurements can help determine the most effective treatments and skincare products for preventing TEWL and maintaining skin hydration. 


You really need these in daily life, but they do exist. Just a little fun fact to talk about at your next dinner party.

I hope this helps you understand TEWL and how it relates to your skin barrier function. 


Now watch your skin glow.

Sonia Roselli skincare defending against TEWL (Transepidermal Water Loss)

Grab your TEWL defenders today:


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