Dry skin affects most people from time to time, often triggered by environmental conditions and personal behaviors. Depending on its severity and persistence, dry skin and its symptoms can be a minor nuisance to some and a significant quality-of-life issue to others. But what is dry skin really, and what causes it? And, most importantly, what is the best way to treat dry skin or even prevent it? In this article, we answer these questions by, almost literally, taking a deep dive into the skin and learn about its intricate structure, basic functions, and the way the right ingredients can help to keep it moisturized and healthy.
What is dry skin?
When we talk about things being “dry,” we typically mean that they are lacking in moisture. And although dry skin definitely lacks water, there is so much more to it than that. Rather than just being dehydrated, dry skin is a condition that is often accompanied by flaking, tightness, and itching, and in extreme cases, cracking and even bleeding. The reason for this is that the skin is not a simple, homogeneous material, but a living tissue with a highly intricate layered structure made up of many different types of cells and molecules that is regulated by complex cascades of biochemical processes, all of which critically depend on the presence of water.
What causes dry skin – introducing the skin barrier
Water is central to any discussion of dry skin, but so is something called the skin barrier. The barrier is a critical function of the skin. Essentially, it prevents bad things like pollutants, chemical irritants, bacteria, and viruses from entering our bodies, and good things, like water, from leaving.
The skin barrier takes the form of the ultrathin, uppermost layer of the skin. It is composed mainly of three things: flattened skin cells, water, and molecules called “lipids.” Think of the cells as tiny shields, protecting you from the outside world, and the water and lipids taking up the space between the cells like the mortar in a brick wall.
The skin’s barrier function prevents chemicals, microorganisms, and viruses from entering our bodies while keeping water inside. The barrier is contained in the ultrathin (as thin as one hundredth of an inch) uppermost layer called the “stratum corneum.” The stratum corneum is made up of flattened skin cells, acting as shields, that are separated by layers of lipids (molecules than have both oil- and water-liking parts) that seal in the moisture.
The skin layer that forms the barrier is called the stratum corneum. Although the stratum corneum may be thin, because it is the uppermost layer of the skin, not only is it our first defense against the environment, it is also the first layer that light interacts with as it touches the skin and is reflected back. Because of this, taking care of your skin barrier is key to healthy, moisturized skin, it also is critical to a beautiful, smooth appearance.
Water, the environment, and the skin barrier
There are two factors that influence the water content of your skin. One is the amount of water in the air around you and the other is the condition of your barrier.
Simply put, the drier the environment you are in, the more water evaporates from your skin. This is why you are more likely to develop dry skin in the desert or in the wintertime or if you spend a lot of time in airconditioned places.
However, if your barrier function is impaired, staying away from dry environments is not enough to avoid dry skin. Having a poor barrier is the same as having a “leaky” stratum corneum that is not doing a good job of holding the water molecules inside and allowing them to evaporate into the air.
We now know that a poor barrier can dehydrate the skin, but the reverse is also true. The ironic thing about the skin barrier is that, while its function is to keep water inside the skin, it itself needs water to do that job. This is because of the fact that the skin barrier periodically renews itself so that every few weeks it is made up of an entirely new set of skin cells. The renewal allows the barrier to stay strong in the face of the environmental insults it is exposed to all the time. You may ask yourself what happens to the old cells. Those are shed, one cell at a time. This is why up to half of the dust in your home is made up of dead skin cells!
How the skin barrier renews itself
One of the most amazing things about the stratum corneum is its ability to both renew itself constantly while remaining structurally intact to provide its critical barrier function. The renewal requires the production of new cells, called corneocytes, that slowly migrate from the base of the stratum corneum to the surface. This migration takes several weeks.
To keep the stratum corneum together the corneocytes are attached by special linkages called desmosomes. However, to be able to shed cells once they reach the surface the skin needs a mechanism to digest these desmosomes. This job is done by specialized enzymes that exist in the upper layers of the stratum corneum, inside the water channels between the corneocytes. These enzymes need water molecules around them to remain stable and functional. If there is not enough water to go around, they stop doing their jobs. When this happens, desmosomes no longer are digested but cells are still migrating towards the surface. The result is corneocytes, still attached to one another, accumulating on the skin surface that can be seen by the naked eye as dry skin flakes or as part of “dehydration lines.”
The constant renewal of the skin barrier is dependent on the functioning of enzymes that digest the linkages between the cells (desmosomes) as they migrate upwards to the surface. In dry skin, there is not enough water to keep the enzymes hydrated. As a consequence, cells are no longer being shed properly and clumps of dry skin cells accumulate on the surface of the skin. If these clumps become large enough, they are visible to the naked eye as skin flakes.
From dehydration to dry skin – the vicious dry skin cycle
When not properly taken care of, it is easy for skin to get stuck in a vicious cycle: Dehydration causes the barrier to weaken, which causes more dehydration, which further weakens the barrier, etc. In addition to increased water loss, an impaired barrier also makes the skin more vulnerable to pollutants and irritants, which can lead to irritation, which, in turn, negatively affects the barrier, adding another element to the cycle…
Also, as we get older, the renewal process slows down, making the barrier more vulnerable, and at the same time the production of essential lipids slows down reducing the water sealing properties of the barrier.
Treating dry skin – breaking the vicious cycle
There are a number of different approaches to breaking the vicious dry skin cycle and achieve healthy, moisturized skin:
Do no harm – eliminating the negatives
One often made mistake is to skimp on a facial cleanser or washing frequently with high-foaming cleansers or soap bars. Cheap or aggressive cleansers tend to contain harsh surfactants (cleansing molecules) that can strip the barrier of the essential lipids that help seal in the moisture or damage the proteins that are critical for barrier renewal. Therefore, a high-quality, mild facial cleanser is an essential first step to treating dry skin. Whatever you do, if you have dry or sensitive skin, your face should not come even in the vicinity of a soap bar, ever.
When it comes to the sun and UV radiation, you should realize that even if you’re not getting a sunburn, UV light and the free radicals it can generate can still damage your skin and your barrier. So, if you go out into the sun, make sure to always use an SPF of at least 30. In the short term this will provide extra protection to your barrier, while you are slowing down longer-term skin aging.
Humectants to attract moisture
Although water is critical to healthy skin, soaking your skin in water is a losing strategy because it actually dries out your skin. What is a winning strategy is to use a moisturizer formulated with powerful humectants. Humectants are molecules that have the ability to attract water molecules and hold on to them. Humectants frequently found in skincare products like Glycerin and Hyaluronic acid are absorbed by the skin and attract moisture from the air and also help the skin hold on to the water molecules that are already there.
Occlusive oils to lock in moisture
Occlusives are molecules that are able to form a layer on top of the skin that effectively seals in moisture by preventing water from evaporating. It’s like a temporary barrier on top of your real barrier that takes over its duties and giving it a chance to heal. Traditional occlusives like petrolatum and mineral oil are used less and less because of their greasy skin feel and environmental concerns. They also tend to clog up pores making them unsuitable for acne prone skin. Modern alternatives like Squalane, plant-based Esters and Silicones provide a superior balance between performance, skin aesthetics, and environmental profile, while being suitable for a wide range of skin types.
Replenishing barrier lipids
The lipid molecules that are critical to a healthy skin barrier – Ceramides, Fatty Acids, and Cholesterol (bad for your heart, but great for your skin!) – are produced by the skin itself but that ability deteriorates with age, and also, they can be stripped from the skin by detergents and solvents. Luckily, they can be replenished from topical creams.
Minimizing irritation
As mentioned above an impaired barrier can cause skin irritation and vice versa. Therefore, and particularly if you have sensitive skin, it is very important to keep any kind of irritation in check. Proven soothing agents you can find in many products include Colloidal Oatmeal, Panthenol (Vitamin B5), Niacinamide (Vitamin B3), and Bisabolol.
Product recommendations
The R+F SOOTHE Calming Gel Cleanser is an ideal facial cleanser for dry and sensitive skin, formulated with gentle surfactants, barrier-protecting Glycerin, and skin-calming Bisabolol.
Both the R+F SOOTHE Daily Mineral Sunscreen SPF 30 and REDEFINE Triple Defense Cream Broad Spectrum SPF 30 provide the sun protection you need and moisturize your skin at the same time.
For the ultimate in skin hydration look no further than the R+F Active Hydration Serum. It is powered by R+F’s proprietary 3D3P Molecular Matrix containing 30% Glycerin and cross-linked Hyaluronic Acid to draw moisture from the atmosphere and lock it on the surface of the skin, as well as essential Ceramides and Cholesterol to restore key barrier lipids.
If you have dry skin that is also sensitive, R+F SOOTHE Moisturizing Rescue Cream is the ideal any-time moisturizer for you with its blend of Colloidal Oatmeal, Ceramides, and Vitamin B5 (Panthenol) to strengthen your barrier and soothe skin irritation.
Senior Director for Innovation and Formulation at Rodan + Fields
