Covering over two square meters, the skin is the largest organ in the human body. While skin appearance has played a massive role in human evolution and culture, biologically, the way our skin looks hardly matters at all. At its biological core, this organ serves as a protective layer β maintaining homeostasis and protecting our vulnerable internal organs from external threats like pathogens and UV radiation.
While every layer of the skin has an essential role to play, its first line of defense is the stratum corneum or skin barrier. Sitting on the surface of the skin, this thin waterproof layer is essential to skin health, but also incredibly vulnerable to damage. Letβs take a closer look at the science behind the skin barrier and what you can do to keep it β and your bodyβs largest organ β protected against external injury. [1]
01
What is the skin barrier and what does it do?
Go ahead and touch your cheek. What youβre feeling is the skin barrier, which sits on the surface of the epidermis, the uppermost layer of the skin. While itβs incredibly thin, the skin barrier actually looks very much like a brick wall when viewed under a microscope. Dead skin cells serve as the dry bricks, while fatty acids, ceramides and other lipids serve as the mortar. Because of its high lipid content, the stratum corneum does the important work of keeping water locked inside the skin. Stable hydration not only keeps the skin plump and smooth, but also supports its essential regeneration processes and maintains homeostasis within the body. Plus, the stratum corneum keeps out toxins, bacteria, allergens and even offers a natural shield against the DNA-damaging effects of UV light. [2]
02
How does the skin barrier maintain balance?
The skin barrier is a delicate ecosystem all its own. Living among our own skin cells are millions of microorganismsβcollectively dubbed the skin microbiomeβthat protect the body from dangerous pathogens and work alongside the immune system, detecting and attacking foreign organisms. Both these microorganisms and the skin barrier thrive at a slightly acidic pH, which keeps harmful microorganisms at bay. When pH levels are off balance, microbiome balance and skin barrier function also suffer, leaving the skin vulnerable to environmental toxins and stressors. [3]
03
What happens when the skin barrier is weakened?
When the skin barrier is compromised, youβre likely to notice signs like redness, irritation, and dryness. But beyond these surface-level symptoms, the skin is struggling with bigger problems.
- Moisture and water loss: When your skin barrier is weakened, more water can escape from your body through the surface of your skin. This can disrupt your bodyβs internal homeostasis and make you more vulnerable to infections and sensitivities.
- Increased vulnerability to sun damage: While wearing sun protection is critical, your skin does have some natural UV defenses of its own. However, these defenses are severely compromised when the barrier is weak, which means your skin is more vulnerable to DNA damage caused by UV radiation.
- Skin infection and irritations: As a physical shield against external pathogens and irritants, the skin barrier keeps the entire body protected. Micro-injuries in the skin barrier allow external irritants to enter the body, leading to everything from minor skin irritation to major infections.
- Weakened immune system: All three layers of the skin contain immune cells. This allows the skin barrier and the immune system to work in tandem, alerting the rest of the body to infections. A weak barrier makes it difficult for the immune system to modulate inflammation, causing an increase in systemic inflammation, which is a precursor to many age-related diseases, including Alzheimerβs disease, cardiovascular disease, and diabetes.
04
How can I tell if my skin barrier is weakened?
Knowing how to spot skin barrier damage is the first step in addressing the health of your skin. Itβs best to catch barrier issues as early as possible: prolonged damage makes it harder to restore the skin barrier back to health, thereby exposing the body to a higher risk of inflammation, infection, and weakened immunity. If your skin barrier is compromised, you will likely experience one or more of the following signs:
- Acne or very oily skin
- Dry or flaking skin
- Heightened skin sensitivity
- Itching or rashes
- Redness and inflammation
- Frequent infections [4]
05
What weakens the skin barrier?
There are some unavoidable aspects of daily life that can weaken your skin barrier: pollution, humidity changes, and genetic skin conditions like psoriasis and atopic dermatitis. But for many people, a weak skin barrier is actually the result of the products they use on their skin.
- Retinol: Although retinol is a beloved anti-aging ingredient, it can severely degrade the integrity of the skin barrier β leading to redness, irritation and peeling.[5] In fact, in a study conducted by OneSkin scientists, we observed that skin that was treated with retinol experienced a βpeeling effectβ that weakened its top layer. Additionally, retinol compromised cellular structure and organization, indicating that the skinβs barrier function had also been negatively altered. [6]
- Sun exposure: UV radiation degrades the proteins that serve as skin building blocks, weakening and thinning skin over time. Sun damage can also make your skin look and act older β leading to decreased barrier function, fine lines and wrinkles, and rough texture.[7]
- Intense exfoliants. Exfoliants can sometimes do more harm than good by stripping away too much of that all-important outer layer of the skin that makes up the skin barrier. In the case of exfoliating, a little goes a long way.[8]
- Harsh cleansers: Face washes that contain harsh detergents like sulfates strip away the lipids that act as the mortar in the skin barrier, creating vulnerabilities that can lead to increased dryness and sensitivity.
- Hot Water: You might love a scalding-hot shower, but your skin barrier doesnβt. Very hot water melts the lipids that keep your skin barrier strong, leading to redness and dryness.
06
How can I protect my skin barrier?
You might be tempted to load your skin care routine with highly active products to see results faster. Resist the urge and your skin barrier will thank you.
- Limit sun exposure and use sunscreen daily. Remember to use sunscreen with an SPF of at least 30 and consider wearing a hat to protect the parts of your body that experience the most direct sun exposure. Itβs also a good idea to avoid the sun at peak hours, which typically occur from 10am to 2pm.[9]
- Be gentle. The skinβs natural defenses work better if theyβre not washed or scrubbed away. Use non-abrasive products that support proper oil production, pH, and microbiome balance.
- Use quality products. What you apply on your skin plays a significant role in how strong your skin barrier is. To protect your skin barrier, avoid products that contain retinol, parabens, or fragrances.
- Support skin barrier function with the OS-01 peptide. In a 12-week clinical study, OS-01 FACE, was shown to increase barrier function by +15%, as shown by measuring participantsβ transepidermal water loss, a key indicator of barrier function. In the lab, our scientists also found that OS-01 FACE induced the formation of a much thicker epidermal layer (dark purple), with a more defined general structure and cellular organization, indicating that skin became thicker and more resilient with improved barrier function when treated with OS-01. [6]
Key Takeaways:
- The skin barrier, also known as the stratum corneum, is the outermost layer of skin responsible for protecting us from environmental threats like pathogens and UV radiation.
- A weak or damaged skin barrier loses its shielding capacity, leading to dehydration, infections, and skin irritations.
- This can show up visibly as redness, breakouts, irritation, and heightened skin sensitivity.
- You can take steps to protect your skin barrier by avoiding harsh cleansers and retinol, reducing sun exposure, and caring for your skin with OS-01, which has been shown in clinical studies to improve barrier function. .
References
- https://www.americanskin.org/resource/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8002265/
- https://pubmed.ncbi.nlm.nih.gov/30130768/
- https://pubmed.ncbi.nlm.nih.gov/31454051/
- https://www.ijstr.org/final-print/nov2016/How-Can-Cosmetics-Cause-Breast-Cancer.pdf
- Zonari, A., et al. Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models. Npj Aging, 9(1), 1-15. 2023.
- https://www.yalemedicine.org/conditions/sun-damage
- https://practicaldermatology.com/articles/2020-apr/the-effect-of-cleansers-on-the-skin-microbiome
- https://www.skincancer.org/risk-factors/uv-radiation/
