How Your Skin Works
Understanding how your skin actually works is the best defence against beauty industry hype. It also might help you appreciate what an extraordinary piece of engineering you're wearing every day, which is never a bad thing.
Your skin is made up of two distinct layers: the epidermis and the dermis.
The Epidermis
The epidermis is the outer layer of your skin. It's the reason your insides can survive in the hostile environment that is the outside world, and it has two main jobs:
- keeping pathogens out
- regulating how much moisture you lose
It's tempting to think of the epidermis as a waterproof membrane sealing everything in, but that's not quite right. Your epidermis allows a controlled amount of water to escape to help regulate your body temperature, while also absorbing moisture from the air and drawing water up from inside the body to keep itself functioning.
The Stratum Corneum
The outer protective layer of the epidermis is called the stratum corneum. Picture it as a brick wall: hardened skin cells are the bricks, held together by a lipid "cement."
This cement is what prevents excessive trans-epidermal water loss, protecting the rest of the epidermis and the dermis beneath from drying out. If the stratum corneum itself dries out, cracks appear, pathogens get in, and more water is lost, a vicious cycle of further drying and further damage.
Those pathogens can cause real problems: spots and acne (bacterial), cold sores and warts (viral), or athlete's foot (fungal). Continually dry skin also tends to age faster.
Cells in the stratum corneum are constantly shed and replaced by new cells generated at the lowest level of the epidermis. As they work their way upward, they harden, die, and release the lipids that make up that cement. Because the stratum corneum is effectively dead tissue, no longer connected to the bloodstream, it can't be nourished from within. It has to be maintained from the outside, with topically applied oils and creams.
At Lyonsleaf, we see this as the real job of a good skincare product: maintaining the stratum corneum from the outside, while the dermis below looks after itself from within.
The Acid Mantle and Your Skin's Microbiome
Sitting on top of the stratum corneum is a very thin, slightly acidic film called the acid mantle, made up mostly of sebum, along with sweat and natural moisturising factors your skin produces itself. While the living tissue beneath is close to neutral (around pH 7), the acid mantle keeps the skin's surface at roughly pH 4.5–5.5.
That acidity isn't incidental. It's inhospitable to many harmful bacteria and fungi, while being exactly the environment your skin's own resident bacteria, your skin's microbiome, thrive in. A healthy microbiome helps keep opportunistic or pathogenic bacteria in check, including some of the bacteria implicated in acne and other breakouts.
The acid mantle matters for the stratum corneum too. The enzymes responsible for producing the ceramide "cement" that holds the brick-wall structure together only work properly within that narrow, mildly acidic range. Push the skin's surface pH up towards neutral or alkaline, and those enzymes become less effective, cracks get repaired more slowly, moisture loss increases, and harmful bacteria and irritants find it easier to get in.
Caring For Your Acid Mantle and Microbiome
Anything that raises skin pH away from its natural acidity works against this system. Most soaps and foaming cleansers are alkaline, and antimicrobial preservatives and antibacterial products don't distinguish between good and bad bacteria, so they disrupt the microbiome right along with anything harmful. Oil-based cleansing avoids this altogether, since it doesn't rely on surfactants that strip the acid mantle or shift the skin's natural pH.
Diagram of the Epidermis
Caring For Your Epidermis
A good skincare routine protects and repairs that lipid cement. Natural oils and butters rich in fatty acids similar to those already in your stratum corneum nourish it, bolster it, and help repair cracks, sealing moisture in. These substances are readily recognised and used by your skin, working with its chemistry rather than against it.
Skin Hydration
You don't actually need to add water to hydrate skin well. Water is naturally drawn up from the dermis below and from humidity in the air. Successful moisturising is really about preventing excessive moisture loss, since that's the underlying cause of dry skin. Adding water to a moisturiser plumps the skin, giving an impressive but temporary feeling of hydration. In fact, too much water contact can disrupt the stratum corneum and become a cause of dry skin itself, which is why people who have their hands in water all day often end up with dry, damaged skin.
A Simple Trick: Apply to Damp Skin
One genuinely useful, evidence-backed technique: apply your balm to slightly damp skin rather than completely dry skin. Emollients and occlusives, the kind found in beeswax and plant butters, work by sealing in whatever water is already sitting on the skin's surface. Dermatologists commonly recommend this exact approach: after cleansing, leave a little moisture on your skin and apply your moisturiser while it's still damp, rather than waiting until it's bone dry. It's a simple habit that makes any water-free balm work harder.
Emollients (Not Humectants)
You'll often see moisturisers described as needing three ingredient types: humectants (which attract water, like glycerin), emollients (which soften and smooth), and occlusives (which seal moisture in). Shea butter and beeswax fall into the emollient and occlusive categories, not humectants, they don't pull extra water in from the air. Instead, applied to damp skin, they seal in the moisture that's already there, which is why the damp-skin technique above matters so much for water-free skincare.
Synthetic Emollients
Petroleum-based synthetic emollients are purely occlusive. They sit on the skin's surface as a film, stopping water loss to some extent, but they also prevent your skin from functioning and drawing in moisture naturally. They can contribute to blocked pores, contact dermatitis, folliculitis, and, ironically, dry skin.
Emulsifiers
Emulsifiers are necessary in water-based creams to blend oil and water together, but on skin, they can cause the lipids in your stratum corneum to mix too freely with water, weakening the barrier by reducing its protective lipid content. By avoiding an aqueous element altogether, we avoid needing emulsifiers in our own formulas. You can read more about why we formulate this way on our Water-Free Skincare Revolution page.
Easily Absorbed Oils
You might assume oil-based products would leave skin greasy, but oils containing short and medium-chain fatty acids (smaller molecules) absorb beautifully rather than sitting on the surface.
Cleansing
Detergents and harsh soaps are also typically alkaline, disrupting your acid mantle and microbiome as well as the stratum corneum's lipid cement (see above). For glowing skin, consider natural soap or, better still, the Oil Cleansing Method, especially on your face.
The Dermis
The dermis is the lower, larger layer of your skin, nourished mainly via the bloodstream. It contains sebaceous glands, hair follicles, nerve endings, sweat glands, lymph valves, and blood vessels, among other things.
Think of the dermis as a matrix of collagen and elastin, a bit like a sponge. Collagen and elastin form the fabric of that sponge, while gel-like substances such as hyaluronic acid fill the gaps, holding water (hyaluronic acid alone can hold up to a thousand times its own weight in water). A well-hydrated dermis looks firm and plump, like a fresh grape. A dehydrated one starts to look more like a raisin.
Collagen, elastin, and hyaluronic acid are all constantly regenerated, though this naturally slows as we age. With the right nutrition, hydration, and protection from free radical damage, you can support that regeneration and slow the visible effects of ageing considerably.
Caring For Your Dermis
Because the dermis is fed by the bloodstream, what you eat affects it directly. A healthy, varied diet and good hydration are the foundations here. Topically applied creams have little direct effect on the dermis, but they do help the epidermis above it stay intact and prevent it from drying out.
Collagen and Elastin
Applying products containing collagen or elastin topically has little value, these molecules are simply too large to pass through the epidermis. If you want to support your own collagen and elastin production, diet and supplements are a more effective route than a topical cream claiming to contain them.
Hyaluronic Acid
Hyaluronic acid is more nuanced. Its molecules come in different sizes: the smallest can reach the dermis and may help it retain water, though there's some debate about how much of a difference this makes. Larger molecules stay in the epidermis, temporarily plumping the top layers and softening the appearance of fine lines, though without lasting benefit.
Formulators aren't required to specify which molecule size they've used. There's also a less obvious downside: because hyaluronic acid attracts water so effectively, in low humidity it can end up pulling water from the dermis below rather than the air above, and that water then evaporates once the epidermis is saturated, drawing more from the dermis in turn. Some research also raises questions about its effect on the skin's more complex anti-inflammatory processes.
If you want to support your body's natural hyaluronic acid production, diet is a genuinely useful lever, and it doesn't work quite the way people often assume. Bone broth is a good example: it doesn't deliver collagen and hyaluronic acid straight to your skin the way a topical product claims to. Instead, digestion breaks it down into amino acids and peptides, which your body then uses as raw materials to manufacture its own collagen and hyaluronic acid where it's needed. It's a slower, indirect route, but a genuinely useful one, and arguably a more reliable investment than an expensive topical serum. See our foods for healthy skin page for more on eating for your skin from the inside out.