Quick note before this post: you may have received a flurry of emails from the blog on Thursday evening. This happened when I was working on the new look for the blog, which unknown to me, began to email subscribers as well as push to my Twitter feed. I’m very, very sorry this happened. I did not expect nor want to blow up inboxes, but here we are. The good news is that the new look is done and shouldn’t cause anymore issue.

Dehydration is characterized by a lack of hydration in the cellular system and intercellular channels of the skin. It is not a skin type, but a skin condition. It does not discriminate between dry, oily, or combination skin types, and is frequently aggravated by lifestyle and skincare choices.

To understand skin dehydration, you need to first understand the role of the natural moisturizing factors (NMF) in skin hydration. The NMF is an invisible lipid composition that sits on the top layer of the stratum corneum (SC) as well as interwoven in the top most layers of corneocytes (skin cells), making up a part in what is considered the “acid mantle” of the skin. The term NMF first appeared in 1959, but was not universally adopted immediately. It is hydrosoluable (able to dissolve in water) and hygroscopic (able to retain water), composed of about 40% free amino acids, 12% pyrrolidone carboxylic acid (PCA), 12% lactates, 8.5% sugars/peptides/inorganic acids, 7% urea, 6% chloride, 5% sodium, and various small amounts of other materials.

It serves three major functions:

1. Protecting skin from damage
2. Encouraging desquamation (exfoliation of the upper most layer of corneocytes)
3. Controlling permeability of the SC

The NMFs are very effective natural humectants, drawing moisture to the skin from the atmosphere, even at humidity as low as 50%. “Hydrated NMF forms ionic interacts with keratin fibers, reducing the intermolecular forces between the fibers and thus increasing the elasticity of the stratum corneum.”² This keeps the skin healthy and supple in appearance. It also serves to prevent excessive water influx (see the third major function above), such as when your skin wrinkles from being in the bath or shower for too long, which causes the corneocytes to shrink.

While it is often thought that the stratum corneum is “dead” tissue, it still requires water to function effectively. The NMF serves to provide for this, drawing and holding much of the water required. For example, enzymes that cause skin cells to exfoliate away naturally, by breaking the various bonds holding corneocytes together, need water to do their job effectively.

Reduction or stripping away of the NMF results in dry skin (known as xerosis), scaling, flaking, as well as fissuring and cracking (such as severely cracked and dry heels). It can also result in what we refer to as “dehydrated skin” (though this is not a medical term).

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What Dehydration Feels Like

Dehydrated skin is one of the more difficult conditions to diagnose because it is frequently invisible. There are many “tips” online about how to diagnose dehydrated skin, such as pinching the back of your hand to see how quickly the skin snaps back into place. It’s important to keep in mind that this only serves to show if your body is dehydrated. Dehydrated skin usually has less to do about the hydration inside of your body and more to do with how we treat the skin topically or the atmosphere around us. This is why someone with dehydrated skin can pinch the back of their hand and see their skin immediately pop back into place, yet feel horrible irritation on their skin when applying a simple moisturizer.

The skin usually looks dry, scaly, or flaky, and feels “tight” (such as after using a harsh cleanser). When pulled very gently, it can appear to crinkle (not to be confused with crepey skin, such as the skin appearance around joints), and can even look like it has a very thin layer of skin sitting atop the upper most layer of skin. It is usually most evident on the forehead or nose. It generally lacks “bounce” and suppleness. In some, it can take the form of crinkly but very shiny skin, usually due to abuse of skin remodelers like AHAs or BHAs.

Both dry and oily skin types can be dehydrated – dry skin because it struggles to hold onto moisture and oily because sufferers frequently use harsh cleansers or astringents to gain relief. According to Milady’s Skin Care and Cosmetic Ingredients Dictionary, “When oily skin becomes dehydrated, the surface layers of cells harden … and block oil secretion. The result is an entrapment of the oils under the stratum corneum layer. This is particularly detrimental in the case of someone with acne because it also results in the entrapment of the infection.”¹

Dehydrated skin also typically responds more viciously to active ingredients, such as BHAs, AHAs, sulfur, retinoids, and vitamin C. It can also respond to completely benign ingredients, creating a burning sensation or the skin feeling flushed and hot.

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Causes of Dehydration

The most common culprits of dehydration of the skin is stripping cleansers, harsh soaps, and hot water, though a host of other causes can come into play.

Skin Conditions

• Atopic dermatitis
• Irritant contact dermatitis
• Psoriasis
• Cutaneous lymphoma

Environmental

• Seasonal changes
• Dry air (low humidity)
• Flowing air (especially wind)
• UV radiation (tanning beds, the sun)
• Overwashing
• Age
• Sunburn
• Cigarette smoking and smoke exposure
• Friction

Heredity Disorders

• Ichthyosis vulgaris
• Netherton syndrome

Hormonal

• Hypothyroidism
• Estrogen deficiency

Topical

• Alcohol/isopropyl alcohol/SD alcohol/denatured alcohol
• Drinking alcohol
• Essential oils
• Clay masks
• Sodium lauryl sulfate
• Bar soap
• Astringents (particularly alcohol-based astringents)
• Topical medications (e.g. retinoids)
• Excessive AHA or BHA use

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Caring for Dehydrated Skin

The most important thing when solving dehydrated skin is consideration of the products you use as well as your environment. This means paying special attention to the ingredients label when shopping, being cautious about what is applied to the skin, and what your home environment is like (and potentially limiting outside exposure to harsh wind and sun).

Since everything starts with your cleanser, this means picking a creamier cleanser or one with lower amounts of surfactants. I’ve done a whole post on cleansers, which you can find here, if you’d like to read about all the various types of cleansers and how they work. The long and short of it is look for either a wipe-off cleansers, such as Albolene; an oil cleanser that emulsifies (rinses clean) in water, such as my beloved Clinique Take the Day off Balm; a creamy cleanser, such as CeraVe Hydrating Cleanser or Aquanil; or a gentle sudsing cleanser, such as Paula’s Choice Hydralight or CeraVe Foaming Cleanser. Avoid washing with hot water, which reduces the size of the micelles (the molecules created from surfactants, which cluster together), allowing them to penetrate deeper into the skin and strip it further. You’ll also want to completely avoid bar soaps (pH is too high) and harsh cleansers that make your skin feel tight after cleansing.

A general rule of thumb is to look for mild surfactants, such as decyl glucoside, or multiple surfactants, like decyl glucoside, coco-glucoside, disodium cocoyl glutamate, disodium laureth sulfosuccinate, cocoyl methyl glucamide, sodium cocoyl isethionate, and lauryl lactyl lactate.

Moisturizers are also a cornerstone in treating dehydrated skin. Humectants are especially important. Some humectants to look for:

• Glycerin – A well-established humectant, it is a clear, thick liquid that is usually sticky on it’s own. It is derived from combining water and fat, usually vegetable oil. It is not typically irritating, but it can be to some people in high concentrations.
• Hyaluronic Acid (HA) – A component of glycosaminoglycan, it occurs naturally in the dermis of the skin and is thought to play a very important role in skin function. It is advertised frequently as holding up to “1000” times it’s weight in water (citation needed). When applied, “hyaluronic acid forms a viscoelastic film in a manner similar to the way it holds water in the intercellular matrix of dermal connective tissue.”¹ It needs application regularly to be effective, frequently breaking down in skin 24-48 hours after application (note: this is not the case with HA injections). It is best applied to damp skin, straight out of the shower.
• Urea – While it is frequently considered more of a moisturizer or keratolytic (able to break down bonds on dead skin) ingredient, urea has humectant properties and can attract and hold moisture in the SC.

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Healing Dehydrated Skin

Armed with the proper ingredients, skin can typically bounce back within about two weeks (14 days). Once healed, skin should be maintained with ingredients and products that are beneficial to the skin’s health.

While healing dehydrated skin, it is recommended to use the most bland routine possible and avoid trying new things and any active ingredients at all. It should go without saying that to heal dehydrated skin, you must drop the products that are creating the problem in the first place. If you must change out one or two products that you believe were causing your dehydration, do so slowly and one at a time, starting with any cleansers and then moving on to moisturizers.

Petrolatum is helpful to some people as well, but can cause problems for others. This is possibly due to it’s ability to diffuse into the intercellular lipid domain of the skin in some people, which interferes with recovery. Your mileage may vary.

It is also recommended to sleep with a humidifier if you are in a particularly dry climate. You want to shoot for somewhere between 40-60% indoor humidity, as this will prevent the humectants from drawing moisture from the deeper layers of the skin, which evaporates away.

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Product Recommendations

Cleansers

Creamy cleansers are ideal for dehydrated skin types, and I have talked fairly extensively about cleansers, with recommendations, in other posts.

For cleanser recommendations, I highly recommend checking out my post about recommended products for rosaceans (and hyper-sensitive skin types).

Hydrators

When it comes to hydrators, I honestly believe that good HA serums can have the biggest impact on dehydrated skin types, especially those that combine several molecular sizes of HA with skin-identifying emollients like squalane (not squalene) and ceramides or other humectants, like urea. Fortunately, the Japanese brand HadaLabo makes several products that meet this criteria and do so inexpensively and without fragrance. The Premium variety is my personal “holy grail” product that I will never be without. You can find Japanese HadaLabo products (listed as simply “HadaLabo” below) on Amazon or in a local Japanese market, while the HadaLabo Tokyo products are marketed for the US marketplace (though contain virtually identical ingredients most of the time) and can be found at drugstores and some Ulta locations.

HadaLabo Goku-jyun Moisturizing Lotion (Normal Skin)

Water, Butylene Glycol, Glycerin, Disodium Succinate, Hydrolyzed Hyaluronic Acid, Hydroxyethycellulose, Methylparaben, PPG-10 Methyl Glucose Ether, Sodium Acetylated Hyaluronate, Sodium Hyaluronate, Succinic Acid.

HadaLabo Goku-jyun Light Lotion (Oily Skin)

Water, Dipropylene Glycol Dimethyl Ether, Alcohol, Glycerin, Disodium Succinate, Hydrolyzed Hyaluronic Acid, Methylparaben, PPG-10 Methyl Glucose Ether, Sodium Acetylated Hyaluronate, Sodium Hyaluronate, Succinic Acid.

HadaLabo Goku-jyun Milk (Dry Skin)

Water, Glycerin, Hydrogenated Poly (C6-12 Olefin), Dipropylene Glycol, Caprylic/Capric Triglyceride, PPG-10 Methyl Glucose Ether, Behenyl Alcohol, Carbomer, Dimethicone, Disodium EDTA, Glyceryl Stearate, Hydrolyzed Hyaluronic Acid, Methylparaben, PEG-20 Sorbitan Isostearate, Phytosteryl/Octyldodecyl Lauroyl Glutamate, Propylparaben, Sodium Acetylated Hyaluronate, Sodium Hyaluronate, Stearyl Alcohol, Triethanolamine.

HadaLabo Goku-jyun Cream (All Skin Types)

Water, Glycerin, Diglycerin, Dipropylene Glycol, Squalane, Caprylic/Capric Triglyceride, Behenyl Alcohol, Carbomer, Dimethicone, Disodium EDTA, Glyceryl Stearate, Methylparaben, PEG-20 Sorbitan Isostearate, Phytosteryl/Octyldocecyl Lauroyl Glutamate, Propylparaben, Sodium Acetylated Hyaluronate, Sodium Hyaluronate, Stearyl Alcohol, Triethanolamine.

HadaLabo Goku-jyun Perfect Gel (All Skin Types)

Water, Butylene Glycol, Hydroxyethyl Urea, Pentylene Glycol, Glycerin, Squalane, PEG/PPG/Polybutylene Glycol-8/5/3 Glycerin, Triethylhexanoin, Ammonium Acryloyldimethyltaurate/VP Copolymer, Agar, Arginine, Dextrin, Dimethicone, Disodium EDTA, Disodium Succinate, Glucosyl Ceramide, Hydrolyzed Collagen, Hydrolyzed Hyaluronic Acid, Methylparaben, Phenoxyethanol, Propylparaben, Sodium Acetylated Hyaluronate, Sodium Hyaluronate, Succinic Acid, Triethyl Citrate.

HadaLabo Goku-jyun Premium Lotion (Dry Skin – My personal holy grail product)

Water, butylene glycol, glycerin, PPG-10 methyl glucose ether, hydroxyethyl urea, sodium acetylated hyaluronate (super hyaluronic acid), sodium hyaluronate, hydrolyzed hyaluronic acid (nano hyaluronic acid), hydroxypropyltrimonium hyaluronate (skin absorbent type hyaluronic acid), sodium hyaluronate crosspolymer (3D hyaluronic acid), aphanothece sacrum polysaccharide (sacrum), hydrogenated starch hydrolysate, glycosyl trehalose, diglycerin, sorbitol, pentylene glycol, triethyl citrate, carbomer, polyquaternium-51, PEG-32, PEG-75, ammonium acrylates crosspolymer, disodium EDTA, potassium hydroxide, diethoxyethyl succinate, disodium succinate, succinic acid, phenoxyethanol, methylparaben.

HadaLabo Tokyo Skin Plumping Gel Cream

water, hydroxyethyl urea, butylene glycol, glycerin, pentylene glycol, PEG/PPG/polybutylene glycol-8/5/3 glycerin, squalane, triethylhexanoin, ammonium acryloyldimethyltaurate/VP copolymer, agar, alpha-glucan, arginine, citric acid, dimethicone, dipropylene glycol, disodium EDTA, glucosyl ceramide, hydrolyzed collagen (marine), hydrolyzed hyaluronic acid, iodopropynyl butylcarbamate, methylisothiazolinone, sodium acetylated hyaluronate, sodium chloride, sodium citrate, sodium hyaluronate, triethyl citrate.

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Sources

1. Milady Skin Care and Cosmetic Ingredients Dictionary,  2014, M. Varinia Michalun
2. Understanding the Role of Natural Moisturizing Factor in Skin Hydration