Hydration is the secret to naturally radiant skin. Poor hydration exacerbates skin problems such as eczema, acne, wrinkles, lack of radiance, itching, and scaling, among others. In this article, you will learn how skin hydration works in order to get the most benefit from it.
The skin barrier and hydration
The outermost layer of the skin, called the stratum corneum, is made up of skin cells packed tightly together, forming a barrier that helps prevent water loss from the skin.
The stratum corneum contains water-based Natural Moisturizing Factors (NMFs), such as amino acids, urea, hyaluronic acid, and lactic acid, which help retain water in the skin. NMFs attract water and bind it to the skin, thus helping to maintain hydration levels and prevent dryness.
In addition to NMFs, the skin contains lipid-based or lipid-friendly substances that help retain water and maintain skin hydration, such as ceramides, cholesterol, sebum, and glycosaminoglycans (GAGs), which are long chains of sugar molecules that help bind water in the skin.
When the skin barrier is healthy and functioning correctly, it can retain water and maintain skin hydration. Conversely, when it is compromised, water can evaporate from the skin more easily, leading to dry and dehydrated skin.
The role of TEWL
Water loss through the skin is a necessary and natural process for regulating temperature and eliminating toxins. But a damaged skin barrier allows too much water to escape, leading to dehydrated skin that is open to pathogens.
The natural process of water loss through the skin is called Transepidermal Water Loss (TEWL), which is the evaporation of water from the skin's surface into the air. The rate of transepidermal water loss is influenced by various factors, such as air humidity, temperature, airflow, a person's age, physical condition, etc.
Where does skin hydration come from?
Hydration can come from both outside and inside the skin. But one is more effective than the other. First, however, here is a quick explanation of the role of electrolytes and osmosis in the skin.
Electrolytes refer to minerals such as sodium, potassium, and magnesium that regulate the fluid balance in skin cells. They also help maintain the electrical charge of the cells and facilitate various cellular processes.
Osmosis refers to the movement of water across skin cell membranes, controlled by electrolytes. The extreme outer layer of the skin can undergo osmosis (think of wrinkled feet and fingers if you stay in the bath too long), but the water will not go any further. In other words, the skin is waterproof (your body has the same weight before and after your bath; it has not become waterlogged). Water moves from areas with a high concentration of water to areas with a low concentration of water, in order to balance the concentration of solutes (such as electrolytes) on either side of the cell membrane.
When we drink water, electrolytes and osmosis help maintain skin hydration and regulate its overall health. When the skin's electrolyte balance is disrupted, for example by excessive sweating or dehydration, it can result in an imbalance of fluid and electrolyte levels in the skin, leading to dryness, flakiness, and other skin problems.
Internal sources of skin hydration include:
- Drinking water: It is important to drink enough water to maintain general hydration, including that of the skin.
- The body's natural hyaluronic acid: This is a substance present in the body that helps retain moisture in the skin.
- Consumption of essential fatty acids: Omega-3 and omega-6 fatty acids are important for maintaining healthy skin and promoting hydration.
- Consuming vegetables/fruits (they naturally contain minerals that are electrolytes): Electrolytes like sodium, potassium, and magnesium are important for regulating fluid balance in the body, including the skin.
External sources of skin hydration include:
- Oily elements in skincare: Applying moisturizing oils or creams containing oily elements to the skin helps create a barrier that seals in hydration and reduces water loss.
- Humectants in skincare: Certain skincare ingredients, such as glycerin, hyaluronic acid, propanediol, or aloe vera, can help increase skin hydration.
- Humidifiers: Using a humidifier in dry indoor environments can help add moisture to the air, which can be beneficial for the skin.
How to care for the skin barrier and minimize TEWL?
The skin barrier can be compromised by various factors, such as the sun, cold, heat, lack of humidity, sweating, hormonal imbalances, and certain skin diseases or conditions. Poor skincare products damage the skin barrier or worsen an already compromised skin barrier.
A very harsh or drying cleanser, as well as over-cleansing or over-exfoliating, are harmful to the skin barrier because they do not leave enough time for the skin to regulate itself before starting the next skincare routine.
Opt for gentle cleansers such as the Triple Action Cleanser. If you work from home or wear light makeup, you only need to cleanse once a day with a single cleanser (no double cleansing). Exfoliants should only be used once or twice a month, and soaps on the face should be avoided. The reason is explained in the next section.
After cleansing, apply serums tailored to your skin's needs. Then, seal the serums with a moisturizer that contains oily elements (yes, for those with acne-prone skin as well).
An alternative to this routine is using the Skin Diligent Bi-Phase DUO. Two serums, one water-based and the other oil-based, work in synergy to provide targeted solutions to skin problems (fine lines, blemishes, lack of radiance, dehydration, enlarged pores, respecting the microbiome, and promoting cellular health) AND, together, they simultaneously hydrate and seal in hydration, so a moisturizer is not needed.
The role of the skin microbiome and skin pH
The skin microbiome is the set of microorganisms that live on and in the skin, including bacteria, fungi, mites, and viruses. These microorganisms play an important role in maintaining skin health and function, and their composition can be influenced by various factors, including skin hydration.
Dry skin can create an environment that is less favorable to certain good microorganisms. In addition, its pH can shift toward a more alkaline level. This can happen because the skin's natural moisturizing factors, which help maintain hydration, are also important for regulating skin pH. When natural moisturizing factors are depleted due to dehydration, the skin's pH can become less acidic and more alkaline.
When the skin is well-hydrated, its pH is generally slightly acidic, in a range of about 4.7 to 5.5. This slightly acidic pH helps maintain the skin's natural barrier function, which is important for protection against external irritants, pathogens, and other environmental stressors.
Studies have shown that the microbiome of dry and dehydrated skin may be less diverse than that of well-hydrated skin, with a lower abundance of beneficial bacteria, which can contribute to various skin problems and premature skin aging. It is therefore important to maintain good skin hydration for it to be healthy.
The use of soap (a product resulting from saponification) alters the skin's microbiome. Soaps are alkaline (have a high pH), which creates an environment conducive to the development of less beneficial strains.
The role of skin microbiome harmony in maintaining a functional skin barrier, JDD Online, Baldwin, Bhatia, 2017.
Key takeaways:
- It is important to limit excess water loss (TEWL).
- Choosing the right cleanser and cleansing routines are essential to avoid skin damage.
- The skin microbiome plays an essential role in skin hydration and aging.
- Drinking water, with a good balance of minerals, is the "fountain" of hydration.
- Avoid soaps on the face.