What is Dehydrated Skin?
By Cynthia Bailey MD. This page was updated on Tue, Jan 29, 2019
How to Fight Dry Skin and Have a Healthier Complexion
Water in skin contributes to plumpness and suppleness and the look and feel of your skin. The water content of your skin will ebb and flow quickly because your skin will absorb environmental water – like from your bath or shower or humid air. It will also lose water to dehydrated air.
How does your skin become hydrated?
Your skin’s outer layer of dead cells is a sort of ‘water proofing,’ protecting your skin from losing too much moisture. This layer, called the stratum corneum, is made up of dead cells (corneocytes) filled with keratin protein that are structured like bricks set in a mortar of lipid.
It’s the keratin protein that absorbs water causing the cells to swell. “Corneocytes can swell as much as 50% in height when fully hydrated” (1) That’s a lot of plumping!! Fully hydrated skin is also suppler than dehydrated skin.
What is dehydrated skin?
Dehydrated skin is skin that has lost some of its ideal water content. Dehydrated skin is more rigid, less supple, and less plump than fully hydrated skin.
But, too much hydration leads to the lipid mortar becoming more permeable too and the skin can become too permeable. This is how occlusion therapy works, such as when medicine delivered under a patch that you wear on your skin.
What is the ideal air humidity for skin?
The ideal relative humidity for balanced skin hydration is 85% (1). Less than that and water can be pulled out of your skin if you don’t intervene.
How do you prevent skin dehydration?
Bathing in water is technically immersing your skin into a very humid environment of over 85% humidity! Skin will soak in the water, holding it in the keratin protein of the corneocytes. Oil applied after bathing prevents evaporation of this water. Most skin moisturizers for general body use contain some oil. Options include mineral oil, petrolatum or – my personal preference – natural botanical oils. (such as my Natural Lotion and Butter)
You can get even more benefit if you use moisturizers with humectants that bind water or act like water substitute in the skin to keep skin plump and supple (such as components of the skin’s NMF or natural moisturizing factor). These small NMF molecules cozy up to the keratin protein and act like water to help it swell, thus preventing the skin from losing suppleness (aka becoming functionally ‘dehydrated’). Excellent NMFs include glycerin, urea and NaPCA.
Did you know that the outer surface of the stratum corneum has less water and is more prone to dryness than are deeper layers of the skin? Also, skin water content is lower with age. (3)
Why doesn’t your skin loose all it’s water in low humidity weather?
The integrity of the brick and mortar protein/lipid structure is responsible for the structural integrity of your waterproofing. When healthy, it holds in some water. When damaged, it does this less well.
What are the best products to treat dehydrated skin?
Apply products with glycerin, hyaluronic acid (another water-binding ingredient), urea, sodium PCA, squalane (another emollient that maintains supple skin), oils and ceramides. For facial care, my Deeply Hydrating Trio helps reverse dehydration.
For body skin care, my Natural Face and Body Lotion and Face and Body Butter are rich in water trapping oils and vegetable glycerin. Apply a generous layer to your skin right after toweling skin dry when you step out of the shower.
What is dry skin?
“Dry skin” is damaged skin with compromised stratum corneum. Dermatologists call it xerosis. It indicates a disruption in the stratum corneum that can lead to asteatotic eczema (also called xerotic eczema). It happens in relative low humidity environments, especially when skin is exposed to hot water and harsh soaps that pull out the lipid mortar that’s important for structural stratum corneum integrity. This can lead to denaturation of the keratin protein too for further damage. Transepidermal water loss increases (TEWL) and skin eventually breaks down in eczema – dry, itchy, red, scaling and sometimes oozing patches.
Skin repair mechanisms start dropping off at about age 55 which is why we are more prone to this as we age. Parts of your skin most prone to this are your arms and legs, though any part of your skin is at risk.
How do you prevent and treat dry skin?
Use cooler water to bathe and only gentle soaps. Always apply a rich moisturizer after toweling dry (within the magic 3 minute rule) to replenish skin lipids and hold water into your skin. The use of mild acids as skin moisturizers has been shown to enhance skin barrier repair and help prevent xerosis. It is why I am such a fan of glycolic acid body care products. (4)
In summary, how you take care of your skin determines how supple it is, how it looks and how it feels. Avoid harsh soaps.
Apply moisturizer after your bath or shower. Use my Natural Lotion or Butter. If you are older (like many of us), add glycolic acid to your skin care routine. Use it twice a week on your body. My Ultra-Fast Triple Action Skin Smoothing Kit does the trick.
If you want to plump crepey and limp skin so that it looks dewy supple, use water binding ingredients or substitute NMF ingredients in your skin care. My Deeply Hydrating Trio does the trick.
For even deeper healing of dry skin, boost the Daily Face Cream with one of my Facial Booster Oils by placing a few drops in your palm with a dollop of cream, blending together and applying to your face and neck.
- Enamul Haque Mojumdar, Quoc Dat Pham, Daniel Topgaard & Emma Sparr , Skin hydration: interplay between molecular dynamics, structure and water uptake in the stratum corneum, Nature, Scientific Reports; volume 7, Article number: 15712 (2017) Published 16 November 2017
- Barry M. Popkin, Kristen E. D’Anci, and Irwin H. Rosenberg, Water, Hydration and Health Nutr Rev. 2010 Aug; 68(8): 439–458.
- Potts Russel O, et. al., Changes with Age in the Moisture Content of Human Skin, Journal of Investigative dermatology, 82;97-100, 1984
- James William D, Berger Timothy G, et. al., Andrews Diseases of the Skin, 12th Edition, Elsevier, Inc, 2016, page 76-77