Hydration is the secret to naturally radiant skin. Poor hydration worsens skin problems such as eczema, acne, wrinkles, dullness, itching, and flaking, among others. In this article, you will learn how skin hydration works 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 tightly packed 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 properly, it can retain water and maintain skin hydration. Conversely, when it is compromised, water can evaporate more easily from the skin, leading to dry and dehydrated skin.
The role of TEWL
Water loss through the skin is a necessary and natural process of temperature regulation and toxin elimination. 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, age of the person, body 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. But first, here's a quick explanation of the role of electrolytes and osmosis on the skin.
Electrolytes refer to minerals such as sodium, potassium, and magnesium that regulate water balance in skin cells. They also help maintain the electrical charge of cells and facilitate various cellular processes.
Osmosis refers to the movement of water across the membranes of skin cells, 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 further. In other words, the skin is waterproof (your body weighs the same before and after your bath, it has not absorbed water). Water moves from areas of high water concentration to areas of low water concentration, to balance the concentration of solutes (such as electrolytes) on both sides 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, flaking, and other skin problems.
Internal sources of skin hydration include
- Drinking water: It is important to drink enough water to maintain overall 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 oils or moisturizing creams containing oily elements to the skin helps create a barrier that seals in moisture 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 sun, cold, heat, lack of humidity, perspiration, hormonal imbalances, and certain skin diseases or conditions. Poor skincare products damage the skin barrier or worsen an already compromised skin barrier.
A very aggressive or drying cleanser, as well as too frequent cleansing or exfoliation, are detrimental to the skin barrier, as they do not allow 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 corresponding to your skin's needs. Then seal the serums with a moisturizer that will contain oily elements (yes, for those with acne-prone skin too).
An alternative to this routine is to use Skin Diligent's Bi-Phase DUO. Two serums, one water-based and one oil-based, work synergistically to provide targeted solutions for skin problems (fine wrinkles, imperfections, dullness, dehydration, enlarged pores, respect for the microbiome, and promotion of cellular health) AND, together, they hydrate and simultaneously seal in moisture, so a moisturizer is not necessary.
The role of the skin microbiome and skin pH
The skin microbiome is the collection 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 a less favorable environment for certain good microorganisms. In addition, its pH can shift to 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, with a range of approximately 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, dehydrated skin can 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. Therefore, it is important to maintain good skin hydration for healthy skin.
Using soap (a product of saponification) alters the skin's microbiome. Soaps are alkaline (have a high pH), which creates an environment conducive to the growth of less beneficial strains.
The Role of Skin Microbiota 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 prevent skin damage.
- The skin microbiome plays a vital role in skin hydration and aging.
- Drinking water, with a good balance of minerals, is the "fountain" of hydration.
- Avoid soaps on the face.