Transepidermal Water Loss and What You Can Do To Prevent It


As we’ve heard time and again, one of the best ways to achieve healthy looking skin is keeping it sufficiently hydrated. We do this by drinking enough water and avoiding harsh products that might dry it out. Another factor in the equation is something called Transepidermal Water Loss (TEWL). Though it sounds concerning, it’s nothing to panic about. We all experience TEWL at different times throughout the day, the key is to prevent it from happening in the first place. Before we explain how to do that, let’s take a closer look at TEWL and get some questions answered.

What is Transepidermal Water Loss and What Symptoms Does it Cause?

As the name suggests, TEWL refers to a simple physiological phenomenon that occurs when the water evaporates through the epidermis (or outer layer of the skin) and into the air.1 It occurs even more when the protective skin barrier is damaged or impaired—something that happens quite frequently for those who suffer from skin conditions like rosacea or dermatitis­.2 The result is dry, dehydrated skin accompanied by the usual suspects of symptoms: flaking, roughness, redness, tightness, increased visibility of fine lines and wrinkles, the list goes on.

What Environmental Factors Triggers TEWL?

Anything that affects the level of moisture going in or out of your skin is a culprit. Let’s look at the factors that top the list as the worst offenders.

  • Cold, dry, low humidity climates
  • Spending an excessive amount of time in drying conditions indoors caused by air conditioners and heaters3
  • Over-exfoliating or over-scrubbing the skin
  • Using harsh cleansers and other products
  • Sunburns
  • Chlorine
  • Age (as our collagen and sebum production slows)

Our Top 3 Tips to Help Correct TEWL

The key to preventing, or at the very least minimizing TEWL, is locking moisture in and taking care of that skin barrier as best you can. Here are 3 important things you can do to help the situation.

  1. Use a good moisturizer – Choose one that’s a little richer (and still works for your skin type) to lock in moisture and help prevent water loss, especially when you sleep. In addition to a good moisturizer, you may want to also add a hydrating serum to use before your moisturizer to really bump up the hydration.4
  2. Avoid harsh products – High-pH face washes and soaps have a bad reputation for stripping the skin’s moisture. Stick to gentle, moisturizing cleansers that add moisture to your skin and stay away from exfoliating while you’re at it.
  3. Invest in a humidifier – Humidity is your friend here, so anything that adds moisture to the air will help keep skin balanced and hydrated. A humidifier is an especially good idea if you live in an area with low humidity.5

If you feel like your skin is drier than usual or you suffer from a skin condition like rosacea, you should definitely do what you can to keep moisture in to help control TEWL. Need help finding the right products for your skin type? Speak to your dermatologist to get some recommendations and remember to stay hydrated.


  1. Helen Alexander, Sara Brown, Simon Danby, Carsten Flohr, Research Techniques Made Simple: Transepidermal Water Loss Measurement as a Research Tool, Journal of Investigative Dermatology, Volume 138, Issue 11, 2018, Pages 2295-2300.e1,ISSN 0022-202X. Retrieved from:
  2. Addor FA. Skin barrier in rosacea. An Bras Dermatol. 2016;91(1):59-63. doi:10.1590/abd1806-4841.20163541. Retrieved from:
  3. Koseki, K., Kawasaki, H., Atsugi, T. et al.Assessment of skin barrier function using skin images with topological data analysis. npj Syst Biol Appl 6, 40 (2020).
  4. Lynde, C. W. (2001). Moisturizers: what they are and how they work. Skin Therapy Lett, 6 (13), 3-5.
  5. Ohno H, Nishimura N, Yamada K, Shimizu Y, Iwase S, Sugenoya J, Sato M. Effects of water nanodroplets on skin moisture and viscoelasticity during air-conditioning. Skin Res Technol. 2013 Nov;19(4):375-83. doi: 10.1111/srt.12056. Epub 2013 Apr 17. PMID: 23590637.