Dry skin, dehydrated skin and transepidermal water loss (TEWL): what are they and how do they change your skin?

• What is dry skin?
• What is dehydrated skin?
• What is transepidermal water loss (TEWL)?
• How can we treat dry and dehydrated skin?
  • Step 1) Exfoliate
  • Step 2) Hydrate
  • Step 3) Moisturize
• You are now on your way to better, more moisturized and plump skin!
• A final note on choosing skin care for hydration and moisturization:

Did you know that dry skin and dehydrated skin are not the same thing? Yes, it can be confusing. But, when we talk about moisturizing and hydrating the skin, we are referring to two separate actions. Though, they have one goal. That is: to prevent transepidermal water loss (TEWL).

Allow us to explain!

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What is dry skin?

Dry skin is depleted mainly of oil. We often think of oil as a ‘bad’ thing, because it is linked to acne breakouts. However, your skin is partially composed of lipids (i.e. fats, including cholesterol). This is why some skin care products aim to build up ceramides, for instance. Ceramides are a type of lipid that hold skin cells in place.

You also have sebum glands that produce natural oils on your skin. This oil performs an important function; it is designed to hold water in your skin.

So, some oil is ok – even if you have acne.

Dry skin symptoms include flakiness, itching and cracking of the skin. Dry skin may also feel ‘tight’ and irritated.

A person can have a dry skin type, but not a dry skin condition.

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What is dehydrated skin?

Dehydrated skin is depleted of water. Your skin should contain between 10% – 35% water. This is what makes it supple and plump.

When you pinch your skin, it should bounce back easily. But, dehydrated skin will look wrinkled for a moment after pinching.

Dehydration is also what causes wrinkles and deep, dark circles under your eyes that seem to come and go. When skin looks ‘dull,’ it is usually dehydrated.

A person can not have a dehydrated skin type. They can have a dehydrated skin condition.

Dehydrated skin results from transepidermal water loss (TEWL), which we’ll explain below.

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What is transepidermal water loss (TEWL)?

Transepidermal water loss (TEWL) is your skin’s inability to retain water at sufficient levels. Essentially, water evaporates out of your skin more quickly than it can hold on to it. Or, the level of incoming water in the skin is unable to keep up with the rate at which it loses water.

Remember: skin is an organ. When skin experiences transepidermal water loss, it becomes harder and harder for it to maintain its function. Part of this function is to build a barrier that keeps water in. So ironically, water loss leads to even more water loss.

Transepidermal water loss can be caused by:

• Inherent skin conditions such as rosacea or eczema.
• Bodily health issues that affect sweat production and sebum production. For example, conditions such as allergies, diabetes, kidney disease or hypothyroidism can lead to dry, dehydrated skin. Aged skin is also prone to sebum production inefficiencies, leading to the same issue.
• Depleting skin products, such as alcohols or detergent soaps. Some medications can also strip the skin of oil and water.
• Swimming in pools (due to the chemicals therein that dry the skin).
• Excessive washing and scrubbing of the skin, especially with hot water and soap.
• Dry weather, or even dry indoor air (whether hot or cold).
• Skin trauma or irritation from UV exposure, sun burns, dermatitis, wounds, etc.
• Unhealthy foods (such as alcohol, and caffeine, which are diuretics).

If you experience skin dehydration or dryness, you’ll want to avoid any of the above triggers that may apply to you. Or, you can find ways to balance the ones you can’t completely avoid.

For example, if you live in a dry climate, or are susceptible to dry winter weather, try using a humidifier in your home. If you have skin conditions that leave you perpetually dry, seek medical treatment for them. There are, of course, plenty of skin care products to help with dry, dehydrated skin.

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How can we treat dry and dehydrated skin?

To answer this question, let’s consider how your skin naturally functions. Skin produces both water and oil (it’s more complicated than that, but we’re keeping things simple here). Water makes your skin supple, and oil prevents the loss of that water by ‘locking’ it in. When this happens properly, your skin is what we call, “moisturized.” When your skin is moisturized, it can do what it needs to do, as the organ that it is. Collagen and elastin production, cell turnover, wound healing and all that good stuff takes place in moisturized skin. If we can keep that cycle going, we end up with skin that looks healthy and ‘glowy.’

So, when you want to treat dry and dehydrated skin, you’ll want to follow in the same vein. In other words, try to mimic nature.

Follow these three simple steps:

1. Exfoliate
2. Hydrate
3. Moisturize

Below, we’ll delve into these steps in more detail.

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Step 1) Exfoliate

First, get rid of the dry, dead skin cells in the epidermis (i.e. the top layer of skin). These are blocking your absorption of nutrients, water and moisturizers. Do this with a gentle exfoliant. Over-exfoliating can lead to microtears, redness, irritation and other issues (including more dryness).

Important: when exfoliating the skin, be absolutely certain you are using sunscreen during the day. Ingredients in many exfoliating skin care products can make you extra sensitive to sun damage from UV rays. UV rays penetrate windows and are active even on cloudy days. Try our quality sunscreens, here.

At this point, DO NOT leave your skin exfoliated and exposed without the next steps mentioned below! You may otherwise be left with drier, more irritated skin.

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Step 2) Hydrate

Next, use ingredients that bind to water, or draw in water. These are called humectants.

Humectants can include:

• Hyaluroanic acid
• Squalane
• Glycerin
• Sorbitol
• Propylene glycol
• Panthenol
• Lactic acid
• Glycolic acid
• Cetyl alcohol
• Stearyl alcohol
• Aloe

And more.

These types of ingredients come in many skin care products, especially high-quality ones. Some can be bought as stand-alone, or ‘feature ingredient’ products.

The most popular of these is likely going to be hyaluronic acid (HA). HA attracts water from the air, and holds 1000 times its weight in water. It comes in different molecular weights, to ‘fit’ into different layers of the skin.

When a product includes more than one humectant, or a humectant with other skin-boosting qualities (such as peptides, occlusives, UV protectors, antioxidants, etc.), it is likely well-made. Of course, percentages matter, too, and these are not always revealed. So, just because a product lists any or all of the above ingredients, that doesn’t mean it’s using a lot of them.

Using humectants in the form of serums can help with absorption. However, humectants can also come in creams and ‘heavier’ set formulas, which we’ll talk about below.

To keep things simple, for this step, be sure to look for the above water-binding ingredients in a non-irritating, non-comedogenic formula. Preferably your chosen product will avoid (or use very little) drying alcohols, drying essential oils or drying fragrances. These can abound ‘out there.’

After you have hydrated with a humectant, you’re still not done! Next, you need to mimic your skin’s ‘lock in’ step…

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Step 3) Moisturize

After a humectant, follow with fats that ‘lock in’ the water. These are called occlusives and emollients. Occlusives are the ‘protective top sheet’ in skin care, and emollients help to fill in your skin’s ‘cracks.’

While we can call these ‘fats,’ they are not the same as oils that you’d use in cooking. They are designed to mimic the skin’s fats. They are not always pore-clogging, either.

Occlusives and emollients can include:

• Petrolatum (like, petroleum jelly)
• Lanolin
• Dimethicone
• Silicone
• Isopropyl palmitate
• Ceramides
• Shea butter
• Jojoba seed oil, mineral oil (and many other oils in an emulsification)

This list could go on. Theoretically, it could include oils such as sunflower oil, olive oil, coconut oil, argan oil and others that you can buy as standalone ingredients. However, these generally sit on top of the skin as a top ‘film,’ and don’t always penetrate deeply enough to really, truly moisturize. They may end up just clogging your pores. They are not water-adders or carriers, either.

However, many emulsifications (mixtures) made in a proper cosmetic lab are designed to get inside the skin – even if they include these types of oils (or derivatives of them). This is what can make some skin care products superior to using oils you typically find in your kitchen.

It’s not bad to use ‘straight-up oils’ on your skin, per se (some can be great). But, just don’t expect the results you’d get from a skin-specific formula made in a lab by a chemist working with doctors and dermal experts!

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You are now on your way to better, more moisturized and plump skin!

While skin care ingredients and their benefits can go on and on, the above tips should give you a primer on the most basic of skin’s needs: exfoliation, hydration, moisturization and the prevention of transepidermal water loss (TEWL).

Yes, antioxidants and collagen-boosters are fantastic. They offer even more skin benefits.

That’s why many of the products we’ve listed above include more than one category of skin care ingredients. It’s quite typical that the ‘good ones’ include ‘skin smoothies’ that your dermal layers will just love.

However, there’s no sense in using a vitamin serum, for instance, if you’re not following the above three steps to keep your skin in tip-top shape. These steps should form your basis for adding on the anti-aging, brightening or skin-tightening boosters that you desire. They help your skin do its main job, to begin with.

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A final note on choosing skin care for hydration and moisturization:

Generally good skincare won’t sting or dry the skin while attempting to achieve an intended effect. However, there are important exceptions to this rule, such as when using products that are known to cause drying at first, until your skin gets used to them.

A good example would be retinoids like retinol (a vitamin A derivative). Retinol is known to be irritating at first. Almost all retinol products should be used once or twice a week at first. Eventually, skin builds up tolerance to it. Then, this ingredient can be very good at keeping skin healthy and smooth.

But, retinol – and others like it – are not always moisturizers. That’s why they should be used with humectants, occlusives and emollients in non-drying skin care products.

Good skincare will also be balanced for pH, and tested for efficacy.

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