How Skincare Really Works Beneath the Surface — And Why Penetration Matters
Your Skin Is More Than a Surface
When it comes to skincare, most people focus on what they put on their skin—creams, serums, and treatments promising visible results. But what’s often overlooked is how incredibly selective your skin actually is.
Your skin barrier isn’t just a surface. It’s a highly evolved biological defense system designed to protect you from the outside world.
The outermost layer of your skin, known as the stratum corneum, is made up of 15 to 20 layers of flattened, dead skin cells held together by lipids like ceramides, cholesterol, and fatty acids. Dermatologists often describe this structure as a “brick and mortar” system: the cells are the bricks, and the lipids are the mortar.
Although this layer is extremely thin—about the thickness of plastic wrap—it’s remarkably effective at blocking most ingredients from getting deeper into the skin. That’s why many skincare products, no matter how luxurious or expensive, never reach the living layers where real change happens.
Why Penetration Is Everything
From a dermatology pharmacist’s perspective, one key factor determines whether an ingredient can move past the surface: lipophilicity—its ability to dissolve in and move through the skin’s lipid structure.
Ingredients that are too water-loving struggle to pass through this lipid-rich barrier. Ingredients that are too oil-loving may dissolve into the barrier but never move beyond it. The most effective ingredients strike a balance, allowing them to travel through both lipid layers and small water channels within the skin.
Vitamin C: Why Form Matters
Vitamin C is a perfect example of why formulation matters.
In its most common form, ascorbic acid, Vitamin C is water-soluble. This means it often stays on the surface, offering limited antioxidant benefits. In contrast, fat-soluble Vitamin C derivatives, like tetrahexyldecyl ascorbate, are designed to integrate into the skin’s lipid structure.
This allows Vitamin C to penetrate deeper, where it can:
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Support collagen production
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Help brighten uneven pigmentation
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Deliver antioxidant protection at a cellular level
Choosing the right form makes all the difference.
Why Oil-Soluble Ingredients Perform Better
This same principle explains why oil-soluble ingredients like retinol, vitamin D, and vitamin E tend to work more effectively than water-based actives.
When ingredients are properly balanced, they can move past the surface and reach living skin cells—where renewal, repair, and visible improvements actually occur.
Unfortunately, many products rely on impressive ingredient lists without considering whether those ingredients can truly penetrate. The result is skincare that feels good but delivers only surface-level results.
When Skin Is More Receptive
There are moments when the skin becomes more receptive to penetration.
After exfoliation or professional treatments like chemical peels or microdermabrasion, the barrier is temporarily disrupted. This creates an opportunity for well-formulated, gentle, lipophilic ingredients to penetrate more effectively and support visible repair.
Hydration also plays a role. When skin is slightly damp, the outer cells swell and loosen, opening micro-pathways that allow ingredients to move more efficiently. Applying skincare to freshly cleansed, damp skin can significantly improve absorption.
What Science Teaches Us About Delivery
In pharmaceutical science, delivering ingredients through the skin requires precise engineering. Transdermal systems are carefully designed to optimize oil–water balance and penetration—never by accident.
Skincare works best the same way. Gentle exfoliation, warmth, and proper formulation all help ingredients reach where they matter most.
Smarter Skincare, Better Results
Understanding penetration changes how you approach skincare. Instead of layering countless products, you can focus on formulas designed to work with your skin’s biology—not against it.
When ingredients reach living tissue, they can truly support skin function, repair, and long-term health. That’s when skincare moves beyond surface beauty and into real, visible results.
By Benjamin Knight Fuchs, R.Ph.
