What Is Your Skin Barrier, and Why Should You Protect It?
Written and Reviewed by: Elysium Health
- The outer layer of your skin faces the world and protects you from it by limiting water loss, blocking harmful substances from entering your body, and preventing infections. Taken together, these tasks are known as barrier function.
- Barrier function is not only essential for your overall health, it is strongly correlated with skin appearance.
- Barrier function can be negatively affected by aging, environmental factors, and harsh skin care practices.
- You can help maintain a healthy barrier function with proper skin care and by supporting your skin’s natural regenerative processes.
- Mosaic: Developed with the advisement of Dr. Granstein, a world-renowned dermatologist, Mosaic is a daily softgel that combines hyaluronic acid with carotenoids to increase skin moisture, reduce water loss, improve resilience against stressors, and help maintain collagen and elastin production to support a healthy skin barrier for visibly youthful skin.
- Basis: Clinically proven to raise NAD+ levels by 40%, Basis supports ceramide and collagen production, in addition to hundreds of other cellular processes for healthy skin and healthy aging.
What is the skin barrier?
Your skin is composed of three layers: the epidermis, dermis, and hypodermis. These layers differ significantly from each other in structure and function. The epidermis is the body's first line of defense and creates a barrier between the inside and outside of the body. Its main functions are to limit water loss, block harmful substances from being absorbed, and prevent infections.
Figure 1. Layers of the skin
The epidermis is made up of five sub-layers formed through a process called keratinization, where skin cells (keratinocytes) grow and mature. The outermost layer of the epidermis (the stratum corneum) is made of corneocytes—dead, differentiated keratinocytes filled with the protein keratin—embedded in a matrix of lipids (fats) like ceramides, cholesterol, and free fatty acids. The cells and lipids in the stratum corneum (SC) are arranged in a “brick and mortar” pattern and play an essential role in forming the skin barrier by preventing excessive loss of water, ions, and proteins.
Figure 2. Brick and mortar structure of the stratum corneum
Why is skin hydration essential?
Water naturally evaporates through the skin into the external environment due to differences in water vapor pressure gradients. This is a normal process and it’s called transepidermal water loss (TEWL). TEWL is used as an objective measurement of skin integrity, specifically the amount of water lost across the SC. Excessive TEWL, however, can lead to skin dryness, redness, and irritation, and can be detrimental to skin health. It’s both a cause and result of impaired barrier function.
Figure 3. Healthy versus impaired skin barrier
How the skin stays hydrated
Maintaining skin hydration is regulated by natural hygroscopic agents like hyaluronic acid (HA) or hyaluronan in the corneocytes that absorb moisture from the air. HA is capable of binding over 1,000 times its weight in water and plays a critical role in retaining moisture. Skin hydration also depends on the orderly arrangement of extracellular lipids (like ceramides) that form a barrier to water loss. Interestingly, HA also interacts with keratinocytes to regulate lipid synthesis and keratinocyte differentiation (the process by which the different sub-layers of the epidermis are maintained).
Factors that impact skin hydration
Various factors can impact TEWL and skin hydration. Genetics and aging play a role but environmental and lifestyle factors can have a significant impact:
Aging and the decline of HA, ceramides, and collagen
Advanced glycation products (AGEs)
Circadian rhythm and time of day
Aggressive skin care practices
What does excessive TEWL look like?
Excessive moisture loss, if not cared for, can lead to impaired barrier function and dry skin. Here’s a closer look at how excessive moisture loss can affect your skin:
Loss of elasticity
Collagen and elastin breakdown
Impaired repair mechanisms
What can I do about excessive water loss?
We can target excessive water loss by controlling external factors (like our environment) and by supporting natural hydrating processes inside the skin. External methods include the use of a humidifier, especially at night when our skin is the most permeable, to reduce overnight TEWL. We can also protect our skin from sun exposure with regular use of sunscreen (up to 90% of visible changes to the skin can be attributed to photoaging or chronic sun exposure). Topical moisturizers can also provide immediate hydration and relief from dryness. However, their use is limited to the area of application and the outer surface of the skin.
There is a growing body of evidence demonstrating the benefits of oral supplements for hydrating the skin from the inside and for stimulating biological processes in the skin to help maintain a healthy skin barrier. In particular, ingredients that support ceramide and collagen production and boost naturally occurring hygroscopic agents in the skin are shown to help maintain a healthy skin barrier and stave off excessive TEWL. Here are some of the science-backed ingredients that have been demonstrated to support skin health and barrier function through oral administration.
Hyaluronic acid, the body’s natural moisturizing agent
Some simple steps for more youthful-looking skin
So now we know there are some science-backed ways to combat excessive moisture loss and maintain a healthy skin barrier. Our daily skin supplement, Mosaic, offers a new step in your skincare routine that works with your natural regenerative processes and drives changes from the inside. Developed under the advisement of Dr. Granstein, a world-renowned dermatologist and Chair of the Department of Dermatology at Weill Cornell Medicine for over 30 years, Mosaic is formulated with hyaluronic acid and a unique Phytonutrient Carotenoid Complex to restore moisture, elasticity, and help maintain natural levels of collagen and elastin. Our NAD+ supplements Basis and Signal provide highly efficient precursors to NAD+ (more efficient than NAM), to counter the age-related decline in NAD+ levels and support ceramide and collagen production for healthy skin.