CeraVe Blog

What is Transepidermal Water Loss (TEWL)?

Icon > Dry, Itchy or Scaly Skin

If you often wake up in the morning with skin that feels dry or tight, you may be experiencing excessive transepidermal water loss (TEWL) overnight. 

What is transepidermal water loss? This term refers to a simple physiological phenomenon: when water passively evaporates through the skin and into the air. This process is completely normal and inevitable. In fact, transepidermal water loss is happening to everyone throughout the entire day, although the process accelerates dramatically at night. 

The average person loses about 300-400ml of water through their skin each day, so how do you keep your skin hydrated to compensate for all that natural water loss? Read on to learn how to protect your skin from transepidermal water loss by strengthening the skin’s natural protective barrier

How Does Transepidermal Water Loss (TEWL) Impact the Skin?

We’ve established that transepidermal water loss is a natural process, but how does it affect the skin? While it’s true that everyone loses moisture through the stratum corneum (the outer most layer of the skin’s surface), excessive transepidermal water loss can result in a range of unwanted effects on your skin..

Signs of skin dehydration and dryness will begin to appear when the rate of water loss from the epidermis is faster than the skin’s ability to rehydrate. If you’re suffering from excessive transepidermal water loss, you will begin to notice some or all of the key indicators of dehydrated and dry skin,including flaking, roughness, and increased visibility of fine lines. Feelings of tightness and discomfort are also signs of excessive transepidermal water loss.

What Causes Transepidermal Water Loss?

Some transepidermal water loss is inevitable due to the nature of the skin itself, but there are several factors that can exacerbate the process and lead to dry, dehydrated skin. These factors include being in low-humidity climates and employing aggressive skincare practices, such as over cleansing or using too many harsh ingredients.

Transepidermal water loss is a constant process that happens to everyone throughout the day. However, by far the most water loss occurs while we sleep. This is due to the way it is intricately linked to the body’s circadian rhythm. The night-time stage of this natural cycle causes our body temperature to go down, our skin temperature to rise and our skin pH to become more acidic – all of which combines to promote transepidermal water loss.

Additionally, many people sleep in very low-humidity environments due to heating or air conditioning, which can make the air dry. Dry air can suck moisture away from the skin’s surface, resulting in that common dry skin feeling when you wake up.

How to Prevent Transepidermal Water Loss

When there is excessive TEWL, skin can get dry to very dry and dehydrated. Fortunately, protecting skin from transepidermal water loss is as simple as following a few easy steps. Firstly, it is all about moisturising the skin then sealing in the moisture, whether that be directly on the skin or in your environment. Here are the best ways to seal in and maximise the skin’s hydration each day:

Use a gentle cleanser

Over cleansing (cleansing too often) and using a cleanser formulated with strong ingredients are two factors that can cause the skin barrier to weaken over time, hindering it’s ability to lock in moisture effectively. As a result, swapping out your current product for a more gentle cleanser will help to keep the skin barrier operating optimally, and prevent the symptoms of TEWL.

We recommend using the CeraVe Hydrating Cleanser twice a day, morning and night. This cleanser was developed with dermatologists to cleanse and refresh the skin, without over-stripping the skin and compromising the natural skin barrier. 

Use a hydrating serum for extra moisture

Adding a serum to your daily skincare routine is an opportunity to prevent transepidermal water loss by delivering powerful concentrations of hydrating ingredients to the skin after cleansing. Our CeraVe Hydrating Hyaluronic Acid Serum contains a high concentration of Hyaluronic Acid, an ingredient that draws moisture into the skin, and helps the skin to retain that moisture. It also contains Vitamin B5 to soothe dry skin. 

Apply moisturiser consistently

To prevent TEWL, be sure to never skip out on the moisturiser. It can be tempting to moisturise only when your skin feels dry, however we recommend applying our CeraVe Facial Moisturising Lotions (AM and PM) daily after cleansing and serums to hydrate, strengthen and maintain the natural skin barrier.

Moisturise your body immediately after showers and baths 

Soaking in a warm bath or taking a nice long shower can be calming for those with dry skin, however water alone is not enough to keep your skin hydrated. TEWL happens on all areas of the skin, not just the face, so we recommend using our rich and thick CeraVe Moisturising Cream over the entire body after bathing to hydrate the skin and seal in moisture.

Maintain a healthy skin barrier

The skin barrier functions as a shield from external aggressors, protecting against irritation and helping the skin take care of itself. A weakened skin barrier and excessive transepidermal water loss often go hand in hand, so supporting the natural skin barrier should help minimise TEWL. Using the gentle, hydrating products discussed above and avoiding harsh scrubs, active ingredients and over cleansing will go a long way to help strengthen the skin barrier and minimise transepidermal water loss.

Use a humidifier 

We know that low-humidity environments exacerbate transepidermal water loss, so using a humidifier is a simple way to avoid this problem. Humidifiers increase moisture levels in the air, and in turn, help to keep skin hydrated. If you live in a dry climate or spend a lot of time in heating or air conditioning, a humidifier may help keep your skin feeling moisturised.

Look after your hands with a hand cream

We put our hands through a lot, with continual exposure to the elements, and repeated washing with soaps and sanitiser. For this reason, the skin barrier on the hands is especially vulnerable to damage, which as we know, can cause excessive TEWL. Our CeraVe Reparative Hand Cream is a deeply moisturising, fast-absorbing cream for dry, rough feeling hands. 

Ingredients That Work to Avoid TEWL

Enriching your skincare regime with highly effective ingredients that help to hydrate, support and maintain the skin barrier can help to reduce the signs of TEWL. Here are some key ingredients to look for in your skincare routine to help minimise symptoms:

Ceramides

Ceramides are natural lipids (oils) that are a key component of the skin. They make up over 50% of the skin and are an essential part of the skin barrier function in the stratum corneum, so continually applying them through skincare, plays an important role in protecting against transepidermal water loss. The CeraVe range was developed with dermatologists to deliver three essential ceramides (1, 3 and 6-11) to the skin. 

Hyaluronic Acid

Hyaluronic acid is a humectant, which means it is powerful in retaining moisture in the skin. Look for cleansers, serums, or moisturisers with hyaluronic acid to build hydration into your skincare routine.

Niacinamide

Niacinamide is a form of Vitamin B3 that can help soothe the skin and lead to an improvement in the skin’s ability to retain moisture.

Glycerin

Like hyaluronic acid, glycerin is a powerful humectant. This ingredient captures water and keeps it in the skin, while also enhancing the penetration of other skincare ingredients. Look for glycerin in emollients, moisturisers and cleansers

Summary

CeraVe’s range of skincare products help maintain the skin barrier while being gentle on the skin. View our full product range for dry skin types or more skincare options containing the ingredients that help protect against transepidermal water loss.