The delivery problem: why most copper peptides fail

Buy four copper peptide serums and you will find four labels claiming a similar percentage. Use them and you will get four different outcomes, several of them indistinguishable from doing nothing.

The ingredient is not the variable. The delivery is.

A barrier doing its job

The outermost layer of skin, the stratum corneum, is a lipid structure — flattened cells packed in a matrix of ceramides, cholesterol and fatty acids. Its entire evolutionary purpose is to keep water in and water-soluble things out.

GHK-Cu is water-soluble and, by the standards of what crosses that barrier easily, bulky. It is close to the worst-case profile for passive absorption: exactly the kind of molecule the barrier was built to exclude.

So a serum that simply dissolves copper peptide in water and thickens it has made a product that sits on top of your skin. Some small fraction may find its way through. The rest stays on the surface until it is washed off or rubbed onto a pillowcase.

This is not a marginal effect. It is the difference between a functioning product and an expensive blue liquid.

Why the label number misleads

A percentage on a carton is a formulation figure. It describes what was weighed into the batch.

It says nothing about three things that decide whether you receive any of it:

Whether it survived the bottle. Copper peptide complexes are not indefinitely stable. Formulation pH, chelating agents, packaging and time all matter. A product assayed at manufacture and never checked again is telling you about a moment that has passed.

Whether it crossed the barrier. Discussed above, and the largest loss by far.

Whether it was measured at all. Most brands do not assay finished product. They calculate. The number is arithmetic, not measurement.

Liposomes, and what they are not

The approach we use in the Aijaé Peptide Serum is encapsulation. The peptide is carried inside liposomes — small vesicles whose walls are built from lipids of the same families your own barrier uses.

The logic is straightforward. A barrier made of lipids does not exclude lipids. A vesicle that reads as familiar can pass where a bare water-soluble peptide cannot, carrying its cargo with it.

In our formula that vesicle wall is built from hydrogenated lecithin and cholesterol. This is worth being precise about, because both ingredients are frequently sold as actives in their own right.

In Aijaé they are not actives. They are the delivery system. They exist to carry copper tripeptide-1 through the barrier, not to act on skin themselves. Any brand listing them among its hero ingredients is padding a list.

What this changes in practice

Two things follow from getting delivery right, and both are noticeable.

The first is that a lower, verified dose in a formula that arrives beats a higher claimed dose that does not. Percentage is not potency. Delivered dose is potency, and it is not printed on anybody's carton.

The second is texture. Encapsulated systems tend to absorb quickly and leave very little behind — there is no oily film, because the lipids are doing structural work rather than sitting on the surface as an occlusive. A copper peptide serum that feels heavy is usually telling you something about its formulation.

The questions worth asking

If you are comparing copper peptide products, three questions separate them quickly.

Is the percentage measured or calculated? Is it measured in finished product, or in the raw material before it went in? And is there a delivery system, or is the peptide simply dissolved in water and thickened?

Most brands will not answer the first two. That is itself an answer.

Our current batch, AJ-0426, was assayed by HPLC at 2.03% copper tripeptide-1 in finished product. The batch number is on your bottle and the certificate is available on request. We think that should be ordinary rather than remarkable.