The Essential Role of Lipids in Skin Health: Understanding the Epidermal Barrier

The 3 Defense Layers of The Skin Barrier

The skin microbiome is a unique ecosystem that acts as a crucial cleanup mechanism on the surface of your skin. Just like your DNA and fingerprints, everyone's microbiome is distinct. It comprises a diverse array of microbes—bacteria, fungi, protozoa, and viruses—that originate from within your own body. Remarkably, the genes present in these microbes outnumber the genes in your human DNA by a factor of 200.

In healthy skin, there is a harmonious relationship between the skin microbiome and the skin barrier, maintaining a delicate balance. When this balance is disrupted, the microbiome can fail to function effectively. This disruption can lead to an altered pH, invasion of toxins, and a range of issues like infections (which are often simply the microbiome responding to clear up debris), a decrease in essential peptides, and increased inflammation. Each person's microbiome is influenced by various factors, including age, body location, and gender.

To support a thriving microbiome, it is essential to nourish it with prebiotics and probiotics found in natural oils, dead skin cells, sweat, and even soil. These elements, along with the oils and minerals present in your skin barrier, help maintain balance. When your skin's environment is clean and nourished, it can thrive without triggering issues like infections, eczema, or rashes. A "less is more" approach to skincare—favoring oil cleansers, avoiding antibacterial products, and minimizing washing—can help maintain this balance.

The microbiome plays a pivotal role beyond skin health; it acts as a detoxification system that cleanses toxic waste from the body. Think of your microbiome and immune system as a complex system working together to break down potential invaders rather than merely fighting them off. A balanced and diverse microbiome supports many vital processes for skin and overall body health.

Unfortunately, modern hygiene practices can disrupt this delicate balance. Factors such as tap water, excessive washing, even natural soaps, oxidized skincare products, alkaline substances, hot water, exfoliation, antibiotics, and environmental pollutants can harm the microbiome. Internal influences, like the foods we consume and our emotional and mental well-being, also play a role.

It's essential to recognize that there are no "good" or "bad" bacteria; each serves a specific function. Much like firefighters responding to a blaze, bacteria appear when needed but are not inherently responsible for skin issues. Healthy bacteria help maintain skin integrity and break down toxins, cellular debris, and excess hormones. A toxic or undernourished terrain will often manifest as visible skin issues such as acne, eczema, wrinkles, and age spots.

By understanding and nurturing your microbiome, you can promote healthier, more resilient skin.

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The Importance of the Acid Mantle

Directly beneath the microbiome lies the acid mantle, a key player in achieving a healthy, radiant glow. This protective layer is composed of sweat, sebum, water, dead skin cells, lactic acid, urocanic acid, fatty acids, and pyrrolidine carboxylic acid. Ideally, the acid mantle should maintain an acidic pH balance between 4.5 and 5.5. Most soaps have a pH of 7 or higher, which disrupts this balance—natural soaps can be even more alkaline, with products like Dr. Bronner's measuring between 8 and 9. A well-functioning acid mantle is essential for maintaining a balanced microbiome and creating a barrier against toxins.

Note: Certain medications can alter the acid mantle, including antihistamines, chemotherapy drugs (like Tamoxifen), Accutane, diuretics, protease inhibitors, and statins.

Debunking the Myth of "Dead" Skin Cells

There’s a common misconception surrounding "dead" skin cells, known as corneocytes, which many people feel compelled to scrub away. These flattened, hardened cells are keratinized and have lost their nuclei and lipid membranes. They lay down tightly, much like roof tiles, playing a crucial role in protecting the layers beneath. Contrary to popular belief, these cells are not truly dead; they actively communicate with the living cells below, sending important chemical signals.

The only genuinely dead skin cells are those that have naturally sloughed off, contributing to house dust. Harsh scrubbing, acid peels, and aggressive exfoliators strip away this vital layer, compromising your skin's health and leaving it vulnerable to toxins. This can result in an overgrowth of bacteria, fungi, or parasites, which manifest as conditions like acne, eczema, or psoriasis. It’s important to remember that the health of your skin is influenced by both your internal and external care.

Extreme environmental factors, such as hot or cold weather and very hot or cold water, can also disrupt the acid mantle. To support it, we recommend minimizing washing, using pH-balanced hydration sprays like our No.2 Mist, and sealing in moisture with our serum oil. By nurturing your acid mantle, you help maintain the integrity of your skin barrier, promoting a healthier, more vibrant complexion.

Understanding Lipids and Their Role in Skin Health

Lipids are diverse, water-insoluble compounds that play crucial roles in the body. They store energy, protect against water loss, and form essential cell membranes. Within the stratum corneum, the extracellular lipid matrix serves as a vital component of the skin's permeability barrier, preventing transepidermal water loss and blocking the entry of external substances.

The epidermal barrier is composed primarily of ceramides—waxy lipid molecules formed from sphingosine and fatty acids—alongside free fatty acids, which are byproducts of fat metabolism in adipose tissue, and cholesterol, a waxy fat molecule produced by the liver. Ceramides are the cornerstone of this barrier, making up about 40% of the lipid bi-layer, which acts as the “glue” that holds corneocytes (the skin's outermost cells) together. This bi-layer consists of ceramides (40%), cholesterols (20-25%), and free fatty acids (20-22%).

In addition to lipids, the Natural Moisturizing Factor (NMF)—composed of amino acids derived from the protein filaggrin within the corneocyte envelope—enhances the lipid bi-layer's structure. This combination provides waterproof semi-permeability, strength, and resilience to the corneocytes. Without this “glue,” the skin would be compromised, similar to having a leaky roof.

When all components of the skin barrier are intact and functioning optimally, the skin can effectively protect against environmental toxins while regulating temperature and maintaining hydration. It also helps shield us from UV damage, enhances sun resilience, and prevents internal structures from leaking out.