Hydration is the secret to a naturally radiant skin. Poor hydration aggravates skin issues such as eczema, acne, wrinkles, lack of radiance, itchiness and flakiness among others. In this article, you will learn how skin hydration works so you can maximise it to your benefit.

The skin barrier & hydration

The outermost layer of the skin, known as the stratum corneum, is composed of skin cells that are tightly packed together, forming a barrier that helps prevent water loss from the skin.

Within the stratum corneum, there are water-based natural moisturising factors (NMFs) such as amino acids, urea, hyaluronic acid, and lactic acid, that help hold water in the skin. NMFs attract water and bind it to the skin, helping to maintain hydration levels and prevent dryness.

In addition to NMFs, there are lipid-based or lipid-friendly substances in the skin that help hold 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 hold onto water and maintain skin hydration. However, when it is compromised, water can evaporate more easily from the skin, leading to dryness and dehydration.


The role of TEWL

We lose water through the skin as 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 and open to pathogens.

The natural process of water loss through the skin is called transepidermal water loss (TEWL), which is an evaporation of water from the skin’s surface into the air. The rate of TEWL is affected by various factors, such as air humidity, temperature, air flow, person's age, body condition, and others.

Where does the hydration of the skin come from?

Hydration can come from outside as well as inside the skin. But one is more effective than the other. But first, here is a quick explanation of the role of electrolytes and osmosis on skin.

Electrolytes refer to the minerals such as sodium, potassium, and magnesium which regulate water balance in the skin cells. They also help maintain the electrical charge of cells and facilitate various cellular processes.

Osmosis refers to the movement of water through the membranes of skin cells, controlled by electrolytes. The extreme outer layer of the skin can undergo osmosis (think wrinkly feet and fingers if you stay in the bath for too long) but water will not go further, in other words, the skin is impermeable (your body has the same weight before your bath and after, it didn’t get engorged with bathwater). Water moves from areas of higher water concentration to areas of lower water concentration, 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 the skin's hydration and regulate its overall health. When the skin's electrolyte balance is disrupted, such as by excessive sweating or dehydration, it can lead to imbalances in fluid and electrolyte levels in the skin, resulting in dryness, flakiness, and other skin problems.

Internal sources of skin hydration include:

  1. Drinking water: Drinking enough water is important for maintaining overall hydration, including skin hydration.
  2. Body’s natural hyaluronic acid: This is a substance that is found in the body and helps retain moisture in the skin.
  3. Eating essential fatty acids: Omega-3 and omega-6 fatty acids are important for maintaining healthy skin and promoting hydration.
  4. Consuming vegetables/fruits (they naturally contain minerals which 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:
  1. Oil elements in skincare: Applying oils or moisturizers with oil elements to the skin helps create a barrier that seals in moisture and reduces water loss.
  2. Humectants in skincare: Certain skincare ingredients, such as glycerin, hyaluronic acid, propanediol, or aloe vera, can help increase skin hydration.
  3. Humidifiers: Using a humidifier in dry indoor environments can help add moisture to the air, which can benefit the skin.


How to care for the skin barrier and minimise TEWL

The skin barrier can be compromised by a variety of factors, such as the sun, cold weather, hot weather, low humidity, sweating, hormonal imbalance and certain skin diseases or conditions. Wrong skincare products damage the skin barrier or aggravate already compromised skin barrier.

A cleanser that is very harsh or drying, and too frequent cleansing or exfoliating the skin are damaging for the skin barrier, because they don’t allow enough time for the skin to regulate itself before the next skincare routine starts all over again.

Opt for gentle cleansers such as Triple Action Cleanser. If you work from home or wear a light makeup, you only need cleansing once a day with one cleanser (not double cleansing). Exfoliators are to be used only once or twice a month and soaps on the face should be avoided. The reason is in the next section.

After cleansing, apply the serums to meet your skin needs. Then seal the serums with a moisturising cream that will contain oil 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 a water-based and the other an oil-based, work synergistically to provide targeted solutions to skin problems (fine wrinkles, blemishes, lack of radiance, dehydration, large pores, microbiome friendly and promotes cellular health) AND together they simultaneously hydrate and seal the moisture, so a moisturising cream is not necessary.


The role of skin microbiome and skin pH

The skin microbiome is the collection of microorganisms that live on and within the skin, including bacteria, fungi, mites, and viruses. These microorganisms play an important role in maintaining the health and function of the skin, and their composition can be influenced by various factors, including skin hydration.

Dry skin can create an environment that is less hospitable to certain good microorganisms. In addition, its pH can shift towards being more alkaline. This can occur because the skin's natural moisturizing factors (NMFs), which help to maintain hydration, are also important for regulating the skin's pH. When NMFs become depleted due to dehydration, the skin's pH can become less acidic and more alkaline.

When the skin is well-hydrated, its pH is typically slightly acidic, with a pH range of around 4.7 to 5.5. This slightly acidic pH helps to maintain the skin's natural barrier function, which is important for protecting against external irritants, pathogens, and other environmental stressors.

Studies have shown that the skin microbiome of dry, 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 ageing. Maintaining proper skin hydration is therefore important for promoting a healthy skin. 

The use of soap (a product resulting from saponification) alters the skin microbiome. Soaps are alkaline (have a high pH) which create an environment for less beneficial strains to grow.

The Role of Cutaneous Microbiota Harmony in Maintaining a Functional Skin Barrier, JDD Online, Baldwin, Bhatia, 2017

KEY points to take away:

  • It’s important to limit any excess TEWL
  • Choosing the right cleanser and cleansing routines are KEY to avoiding skin damage
  • Skin’s microbiome plays a pivotal role in skin hydration and skin ageing
  • Drinking water, with a good balance of minerals, is the ‘fountain’ of hydration
  • Avoid soaps on face

Leave a comment