Trans-Epidermal Water Loss or TEWL

by Jan 26, 2024Blog

Did you know that your skin loses more than a cup of water each day just through evaporation? For us Albertans, it’s often even more, especially in the winter. This is called Trans-Epidermal Water Loss, or TEWL for short. TEWL accounts for 300-400 mL of water loss on average, with the volume being even more in dryer climates (dry Edmonton winters – sound familiar?) Let’s take a look at how TEWL happens, what we can do to limit it, and how we can keep our skin hydrated and protected.


TEWL happens naturally to everyone, and is your skin’s way of regulating its water content. When the skin’s barrier becomes compromised, whether from dehydration, irritation, or injury, the TEWL will worsen. The best way to prevent excessive water loss is by moisturising, of course. Your moisturiser needs to have three main things to work for you. These are:


  1. Humectants: Your body actually already makes two humectants on its own: Hyaluronic Acid, and Urea. Humectants attract and hang on to water  within the layers of skin. When the air is humid, humectants will attract water from the air, but when the air is dry, humectants will draw water from beneath the skin. Other examples of humectants include aloe vera, glycerin, and honey.

  2. Occlusives: The role of the occlusives is to seal in the humectants. Our body’s natural occlusive is sebum. You know, the oil our skin naturally produces. Some more examples of occlusives are: lanolin, silicone, cocoa butter, and any oil such as jojoba, safflower, or even vegetable or mineral oil.

  3. Emollients: Emollients are intended to give your skin that soft, smooth feeling. They are comprised of oils and lipids such as shea butter, isopropyl palmitate, jojoba oil, almond oil, etc.


In order to properly protect the skin from excessive moisture loss, it is important that we replenish all three categories as needed. This is why only using a hyaluronic acid serum won’t feel like it lasts long enough, just like only using a thick occlusive without any humectants will still leave you feeling dehydrated. It is possible for an ingredient to be both an emollient and an occlusive, as you can see with jojoba oil.


Dry or dehydrated skin will lead to a compromised barrier (as does irritated or injured skin, even after controlled injuries such as ablative or resurfacing treatments) which exacerbates TEWL. That’s right- it’s a vicious cycle of your dry skin making itself drier. Regularly moisturising is the best way to prevent too much evaporation, while doubling up on the thicker occlusives can help to mimic a barrier to prevent further damage while the natural barrier repairs itself once compromised.


There are additional factors that contribute to water loss such as the fabrics against your skin. If you wake up each morning with your skin feeling dry, stretched, or creased, it could be because the fabric that you sleep on is absorbent, furthering the loss of moisture from your epidermis. Most pillowcases are made from cotton, an ultra-absorbent textile. Silk and satin pillowcases are an easy to find alternative that won’t suck you dry.


Recommended products for preventing TEWL and protecting your natural barrier:


Circadia Vitamin C Reversal Serum: Hyaluronic acid based serum with the added anti-aging benefits of Vitamin C.

Circadia Post-Peel Balm: This semi-occlusal balm is rich in oils, perfect for mimicking a barrier and sealing in moisture. Active ingredients promote healing and soothing of irritated or compromised skin:

Circadia Vitamin Veil Cleanser: Its an oil-based emollient designed to cleanse the skin while still leaving an ultra-thin film of vitamins and oil on the surface, nourishing and protecting the skin.

Circadia The Pillowcase: The fabric in this pillowcase was specially designed by Circadia’s Dr. Pugliese to prevent TEWL while your face is resting on it!

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