# GHK-Cu transport through skin

> Skin penetration at Miami Stem Cells — Miami Stem Cells examines a GHK-Cu copper-penetration experiment in excised human skin and the delivery problem discussed in a topical GHK review.

A response in a culture dish leaves a separate delivery problem at the skin.

## The excised-skin experiment

A [human skin-penetration study examined copper applied as a GHK-Cu tripeptide](https://pmc.ncbi.nlm.nih.gov/articles/PMC3016279/) in skin outside the body. It measured copper that passed through the tissue and copper retained within it, reporting a dermal depot.

I like the physical question here. A material can have an interesting effect in a cell culture while its behaviour at the skin surface becomes an experiment of its own. Penetration and retention give different answers about where the copper went.

The measurement deserves its exact subject. This study examined copper delivery through skin layers; a claim about how much intact peptide reached a particular target would need evidence about that target and that chemical form. The distinction is easy to lose when the material's familiar name leads the account.

![Illustrated laboratory diffusion chamber holding a thin tissue membrane between glass compartments.](images/skin-chamber.webp)

*Editorial illustration of a skin-permeation apparatus; the arrangement represents the kind of laboratory question, not the specific equipment used in the paper.*

## The retained material

The [study reported copper retained as a dermal depot as well as copper permeation](https://pmc.ncbi.nlm.nih.gov/articles/PMC3016279/). “Absorbed” now seems an oddly imprecise word to me. Retention describes material remaining in a tissue compartment; permeation describes passage through it.

I would want a delivery claim to name which of those achievements it means. A depot can be relevant to local availability, while a statement about delivery elsewhere asks a different question. This experiment's skin-layer setting provides the useful boundary.

It also gives the [collagen findings](/collagen) a practical neighbour. Production in cultured fibroblasts and delivery through excised skin are connected questions, with different measurements.

## The topical-delivery review

A [review of topically applied GHK identifies poor permeability through the outer skin layer as a central challenge](https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/). It considers modified peptide forms and approaches intended to improve passage through skin. The review treats formulation as an active problem in the research.

I give the preparation itself a large share of the attention here. A useful cellular response and a useful preparation require different kinds of work. The delivery discussion explains why the preparation itself deserves scrutiny alongside the peptide's name.

I'd pair the delivery change with a clearly specified biological outcome in a further experiment. More passage through skin would answer a transport question first; clinical benefit would still require its own measurement.

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Miami Stem Cells is my gallery of published research on cellular renewal, with no clinical business behind the name and no medical advice on these pages.