Liposome Delivery in Cosmetics: Carrier Charge and How to Read Penetration Claims

A liposome is a vesicle made of the same lipids that form a cell membrane. Water-soluble substances can be carried inside it and oil-soluble ones within the shell itself, and the point of the construction is that the active keeps better in the formula and distributes differently across the surface of the skin. Liposomes appear often in Korean presentations, usually together with a diagram and an arrow pointing down into the skin.

That arrow does not help a buyer. It is more useful to understand how carriers differ, what penetration testing really shows, and which caveats have to sit next to any claim of this kind.

Cationic, neutral and anionic carriers

Liposomes are distinguished by the charge of the shell. A cationic one carries a positive charge, an anionic one a negative charge, and a neutral one carries no pronounced charge. The charge is set by the lipid composition and by additives, and it determines how the carrier behaves on the skin surface and how stable it is in the formula.

At the usual pH of skin the stratum corneum is negatively charged. From this follows simple electrostatics: a positively charged carrier is drawn to the surface and held there longer, while a negatively charged one is repelled. Most claims about the advantage of cationic systems are built on this.

Retention and penetration are not the same thing

This is where the main substitution in marketing happens. Better retention on the stratum corneum means the carrier stays longer where it was applied and the active has more time to release. That is not the same as passing deeper into the skin, and the second does not automatically follow from the first.

Cationic systems also raise questions of tolerance more often, so a dermatological irritation test is not a formality for formulas of this kind. Ask for it alongside the penetration data rather than instead of it.

How to read a penetration test

A typical test works like this: the active is tagged with a fluorescent reagent, applied to a skin model, and the intensity of the signal is compared across the depth of a section. The result depends on the model, and the difference between a cell culture, ex vivo skin and a living person is fundamental. Ask what the model was and who ran the test.

Then look at the comparison. A sound test measures the carrier against a control, usually a plain aqueous solution of the same active, and shows every variant side by side. And one last point: fluorescence shows the distribution of the tag, not the quantity of active substance delivered. These are close but different measures.

The regulatory frame

Cosmetics by definition act on the surface and in the upper layers of the skin. Claims about delivering an active into the dermis or about systemic action take a product outside the cosmetic category in most jurisdictions, and on a label for the EU or the United States such wordings will have to be softened regardless of how the brand's original presentation sounds.

The practical conclusion for a buyer: the mechanism of the carrier can and should be explained to a distributor and to the professional channel, but carrying it word for word onto the pack is risky. A line about delivering actives deeper belongs in a presentation with its caveats, not as a promise on the box.

The caveats that have to be there

Any penetration claim depends on at least two variables. The first is the specific active substance, because molecular weight and solubility decide more here than the carrier does. The second is the condition of the skin, because a damaged barrier behaves differently from an intact one. A supplier who states these caveats unprompted usually knows what they are talking about.

An example from our showcase. According to CAYCLLY, its Pressome™ delivery technology is a cationic liposome protected by Korean patent 10-2164218. In the company's own fluorescent reagent test the cationic carrier showed the highest absorption, ahead of the neutral and anionic versions and well ahead of a plain aqueous solution. The company itself notes that the result depends on the active substance and the condition of the skin, and that is precisely the caveat most often missing from materials of this type. The test was run by the company itself, so it is worth requesting a copy of the protocol at the deal stage.

What to ask a supplier

On the carrier: type and charge, shell composition, particle size and stability in the finished formula. On the test: the model, the control, who ran it, and whether there is a report describing the method. On the product: which wordings the supplier considers acceptable for your market and what backs them up.

Teranova coordinates and supports checks of this kind: it collects the supplier's data, requests the reports, and shows the buyer where a confirmed fact ends and a line from a presentation begins.