GHK-Cu skin delivery

A close look at the barrier between an ingredient and the cells that interest us.

The skin-layer experiment

The human skin penetration study is an experiment on removed human skin, outside the body. Copper was applied as a GHK-Cu tripeptide preparation, and the investigators measured copper passage through skin layers as well as copper retained in the tissue.

Over 48 hours, the skin-layer experiment reported 136.2 +/- 17.5 ug/cm^2 of copper permeating dermatomed skin and 97 +/- 6.6 ug/cm^2 retained as a dermal depot. “Dermatomed” describes the skin preparation in this experiment. The retained material is an especially useful part of the result: passage through and residence within the skin are different measurements.

I picture this paper as a materials problem before I picture it as an aesthetic one. The preparation, the layer and the measured substance all belong in the account. Copper is the quantity recorded here. A claim about intact peptide reaching a particular cell in a living face asks for additional evidence.

Two technicians inspect glass diffusion cells on a bright laboratory bench — An imagined laboratory scene with glass diffusion apparatus, illustrating the kind of barrier experiment discussed here; no named laboratory or study team is depicted.

Why formulation gets so much attention

The topical GHK review identifies poor stratum-corneum permeability as a central problem. The stratum corneum is the outer skin barrier. Its discussion includes palmitoylation, a modification to GHK, and microneedle pretreatment as approaches to improving delivery.

That turns formulation into a substantive research question. A change in the material or the skin's preparation changes the experiment. Interchangeable preparations seem an especially shaky assumption to me when delivery is the very difficulty the work is trying to solve.

The same review reports about 134 nmol of GHK permeating after microneedle pretreatment, compared with none through intact skin in the experiment it discusses. This is a research comparison in a particular setup. It supplies a reason to investigate delivery and supplies no instructions for performing a skin procedure.

From passage to appearance

The penetration paper establishes a copper-delivery and retention result. The topical review considers delivery alongside anti-wrinkle research. Their productive connection, to my eyes, is a question: how does the amount reaching or remaining in skin relate to a cosmetic outcome?

These experiments do not settle a comparison with injection. There is no basis in the cited skin-layer experiment for choosing a human injection dose, interval or route. Changing the route would change the question and the evidence needed to answer it.

For now, the most concrete place to return is the collagen file, where the reported topical response can be considered alongside the work on cultured cells. The physical barrier deserves its place between them. I could happily forgo another claim of deep penetration if a study tied delivery to a measured skin outcome.