“Penetrates Deeply”: What This Cosmetic Claim Actually Means

Can a cream truly penetrate deep into the skin — and what does that mean?

In the beauty industry, the promise of “deep penetration” has become a cliché — and one that often doesn’t match reality. To understand what’s marketing and what’s science, we need to start with the basics: what cosmetics can and cannot do from a skin chemistry perspective.

Cosmetics are not pharmaceuticals. Their job is to moisturise, nourish, and bring comfort. By law, they are only allowed to act on a surface level — meaning they must not cross the skin barrier into the bloodstream. But even within this “surface-level” scenario, it’s possible to create deep, targeted, active engagement — thanks to science-backed formulations, delivery systems, and synergy with the skin’s receptor network.

What does “deep” mean in cosmetic chemistry?

Skin has several layers. Its outermost defence — the stratum corneum — is made of dead cells. Beneath it is the living epidermis, and deeper still — the dermis. In most cases, cosmetics can only reach the surface of living cells in the epidermis. Penetration into the dermis is only possible in exceptional cases — for example, with very small, fat-soluble molecules (retinol, essential oils) or via invasive methods (like mesotherapy).

So when a brand claims a product “penetrates deep layers,” it’s important to ask: which layers exactly? And is it even necessary?

How active ingredients reach the skin

On their way to living cells, active ingredients must overcome serious barriers. This is especially true for water-soluble ingredients like peptides, vitamin C, exosomes, and growth factors. The skin perceives water as a threat (due to potential bacteria or allergens), so it instinctively repels water-soluble substances.

To help such molecules, formulations use delivery systems: liposomes, nanosomes, or enhancers — substances that temporarily disrupt the barrier to let the actives through. Even under optimal conditions, these ingredients only reach the basal layer of the epidermis. And that’s enough — this is where the receptor network is located, capable of sending signals deeper into the dermis.

Depth isn’t physical — it’s biological

One of the biggest breakthroughs in modern cosmetic chemistry is this: achieving a result doesn’t require physically implanting an ingredient deep into the skin. Skin is a complex signalling system, and activating surface cells can trigger a cascade of effects deeper down.

Examples of such signals:

• A peptide interacts with a surface receptor — the receptor activates a chain reaction in fibroblasts
• Vitamin C stabilises on the surface — triggers antioxidant protection
• The microbiome detects an active — releases cytokines that stimulate dermal regeneration

This is the principle of neurosensory skincare: receptor activation that triggers internal mechanisms of self-repair.

But what about safety?

Here’s what’s important to understand: anything that penetrates “too deeply” (into the bloodstream) must be rigorously tested. That’s why some ingredients — like retinol and certain essential oils — are restricted during pregnancy due to systemic effects. And that’s why 99.9% of cosmetic products are designed to stay within the safe zone — effective, but non-invasive.

How it works in Re[Sens] formulas

Re[Sens] is a high-biotech professional skincare brand focused on sensitive skin. Our formulas combine:

• neurocosmetic technologies
• innovative delivery systems for water-soluble actives
• microbiome-friendly preservation systems

We believe true results come not from aggression, but from a deep understanding of skin biochemistry. That’s why we follow the philosophy of Slow Beauty — creating products that don’t just “penetrate deeply,” but work precisely, effectively, safely — and only where needed.