AHK-Cu Research, Specifications & Scientific Information

Introduction

AHK-Cu is a copper complex of a three-residue peptide, and its published primary research consists of one paper.

That is not an editorial judgement about the compound; it is the result of searching for it. A 2007 study from Seoul National University cultured human dermal papilla cells and maintained human hair follicles in organ culture, applied the complex, and reported elongation of the follicles and proliferation of the cells at concentrations between 10⁻¹² and 10⁻⁹ M ^[1]. No animal study of the complex has been identified. No clinical trial has been identified. Nothing else has been published about it that this page could verify.

What AHK-Cu does have is a structural relative with a long literature. GHK-Cu differs from it by one methyl group — glycine where this peptide has alanine — and has been studied since the 1980s. The temptation with a compound like this is to fill the gap with the neighbour's evidence. This page does not do that, and the reason is set out under the comparison heading below.

This page is a reference record. It describes research. It contains no guidance of any kind on handling the material.

What Is AHK-Cu?

Two things, held together by a coordinate bond.

The peptide. L-alanyl-L-histidyl-L-lysine, a linear tripeptide written AHK in single-letter code. The FDA/NCATS Global Substance Registration System carries it under UNII 1AVY5QO8WR with CAS registry number 126828-32-8, molecular formula C15H26N6O4 and a molecular weight of 354.41 g/mol.

The copper. A copper(II) ion coordinated by the peptide. Peptides with a histidine imidazole close to a free N-terminus are effective copper chelators — the amine, the adjacent amide nitrogen and the imidazole together supply a stable coordination set — and this is the structural feature the Xaa-His-Lys tripeptides share. PubChem records the complex as compound identifier 168431292, under CAS registry number 682809-81-0, with formula C15H24ClCuN6O4 and a mass of 451.39 g/mol, described as a monohydrochloride.

It is not an approved medicine anywhere. It appears in cosmetic ingredient listings, which is a separate regulatory category and confers nothing about efficacy or about laboratory research.

AHK-Cu Specifications

AHK-Cu is a coordination complex, not a peptide alone, and the two halves have separate register records. The free tripeptide L-alanyl-L-histidyl-L-lysine is carried in the FDA/NCATS Global Substance Registration System under UNII 1AVY5QO8WR with CAS registry number 126828-32-8, PubChem compound identifier 7408502, molecular formula C15H26N6O4 and a molecular weight of 354.41 g/mol. The copper complex shown in the table above is a separate PubChem record, compound identifier 168431292, under CAS registry number 682809-81-0, described there as the monohydrochloride of the copper complex of the dianionic tripeptide, with the formula and mass given. No unique ingredient identifier is published for the complex, so that field is shown as unknown. The distinction matters in practice because a complex is defined by its stoichiometry and its counter-ion as well as by its peptide: material supplied as AHK-Cu may differ from the specific monohydrochloride record above, and the peptide-to-copper ratio is a property of the preparation rather than of the name. The certificate of analysis supplied with a laboratory order is the record for a given lot.

Values that a public register does not carry are shown as not publicly characterised rather than estimated. Identifiers are reference values; the certificate of analysis supplied with a laboratory order is the record for a given lot.

How Does AHK-Cu Work?

Not established, and this page states that rather than assembling a plausible account out of adjacent literature.

Three things can be said honestly.

The copper chemistry is real and characterised for the class. Copper(II) binding by histidine-containing N-terminal peptide motifs has been measured directly, including by isothermal titration calorimetry against a weaker competitor, for the closely related peptides GHK and DAHK ^[3]. Those measurements describe the chemistry of a structural family that AHK belongs to. They do not describe AHK-Cu, which was not among the peptides studied.

No receptor has been identified. Not for this complex, and not — despite a far larger body of work — for the copper tripeptide family generally. The literature on GHK-Cu describes effects on gene expression and on matrix proteins rather than a receptor and a ligand ^{[2, 5]}.

The one primary study proposes a cellular rather than a molecular mechanism. Its authors suggested that follicle elongation followed from proliferation of dermal papilla cells together with a reduction in their apoptosis, and supported that with apoptosis-associated protein measurements ^[1]. That is a proposal about which cells are involved. It is not a target.

The specification table shows primary target, receptor family and agonist status as not established, and those entries are accurate rather than incomplete.

AHK-Cu Mechanism of Action

In vitro research

The whole primary record for this compound sits in one experiment, so it is worth setting out in full and reading precisely.

System. Cultured human dermal papilla cells — specialised fibroblasts that sit at the base of a hair follicle and are central to follicle morphogenesis — and human hair follicles maintained ex vivo in organ culture ^[1].

Concentrations. 10⁻¹² to 10⁻⁹ M.

Reported results. The complex stimulated elongation of the hair follicles in organ culture and proliferation of the dermal papilla cells. Annexin V–fluorescein isothiocyanate and propidium iodide labelling with flow cytometry showed a reduction in the number of apoptotic dermal papilla cells at 10⁻⁹ M, and the authors reported explicitly that this reduction was not statistically significant. In the same condition, the ratio of Bcl-2 to Bax was elevated and the levels of the cleaved forms of caspase-3 and PARP were reduced ^[1].

How the authors framed it. As a proposal: that the complex promotes follicle growth, and that the effect may arise from proliferation of dermal papilla cells together with prevention of their apoptosis ^[1].

What is worth noticing. The apoptosis result is a mixed one. The direct measure — the count of apoptotic cells — did not reach significance, while indirect protein-level measures moved in the expected direction. That pattern is consistent with a real but small effect and equally consistent with none, and the study is not powered to tell those apart. Reporting the non-significant primary measure alongside the supporting protein data is what the original authors did, and this page follows them.

What it does not establish. An organ culture is a piece of excised tissue with no circulation, no immune system and no systemic hormonal input. A concentration applied to a culture well is not an exposure achieved in tissue. And a single study, whatever it shows, has not been reproduced.

What Is AHK-Cu Being Researched For?

One thing, once.

• Hair follicle and dermal papilla cell biology — the subject of the single published study ^[1].

No other research area has an identifiable primary literature for this compound. There is no registered clinical trial, no published animal study, and no independent replication of the 2007 result that this page has been able to locate.

The adjacent literature on copper tripeptides — matrix remodelling, gene expression, transforming growth factor beta secretion in dermal fibroblasts — concerns GHK-Cu and is cited on this page only to mark where the boundary falls ^{[2, 4, 5]}.

Current Research Status

Status as of September 22, 2026. This block is rendered from maintained fields, not from prose, so it cannot go stale in one place and stay current in another.

AHK-Cu vs Related Compounds

The comparisons below are structural and evidential. No comparison of effect is made on this page.

GHK-Cu :: Gly-His-Lys complexed with copper(II), against this compound's Ala-His-Lys. The peptides differ by one methyl group on the first residue's side chain. Their evidence bases differ by roughly four decades and several dozen papers.

Why the similarity is not transferable

Single-residue substitutions routinely change the behaviour of short peptides, and the whole field of structure-activity work exists because they do. A page that borrowed GHK-Cu's findings for AHK-Cu would be asserting that this particular substitution is inconsequential, which nobody has tested. The honest position is that the two are chemically analogous and evidentially very far apart.

Copper coordination

Both belong to the Xaa-His-Lys class that chelates copper(II) through the N-terminal amine, the adjacent amide nitrogen and the histidine imidazole. Binding thermodynamics have been measured for GHK and for DAHK but not, in the work located here, for AHK ^[3].

BPC-157 and TB-500 :: Grouped with this compound under repair and regenerative research in this library, and sharing no mechanism with it. The grouping reflects the research questions asked of these compounds, not a common chemistry.

Chemical & Molecular Characteristics

Two register records, one name. The free tripeptide and the copper complex are separate substances with separate registry numbers. Free L-alanyl-L-histidyl-L-lysine: UNII 1AVY5QO8WR, CAS 126828-32-8, PubChem compound identifier 7408502, C15H26N6O4, 354.41 g/mol. The copper complex: PubChem compound identifier 168431292, CAS 682809-81-0, C15H24ClCuN6O4, 451.39 g/mol.

The complex record is a specific salt. PubChem describes 168431292 as the monohydrochloride of the copper complex of the doubly deprotonated tripeptide. That is a more specific description than the bare name AHK-Cu conveys. Material supplied under the bare name need not match that record in counter-ion or in hydration state, and those differences change the mass.

The peptide-to-copper ratio is a property of the preparation. A name of the form "peptide-Cu" does not fix stoichiometry. For a compound whose literature consists of one paper, there is no body of published characterisation to fall back on, which makes the analytical documentation for a given lot the only record of what it contains.

One field is blank on purpose. No unique ingredient identifier is published for the complex by the FDA/NCATS register, although one exists for the free peptide. That field is shown as unknown rather than filled with the peptide's identifier, because they are not the same substance.

Colour is a weak but real check. Copper(II) peptide complexes of this class are coloured, typically blue to blue-violet, where the free peptides are white solids. A material sold as a copper complex that is white is worth questioning against its certificate of analysis.

Frequently Asked Questions

Scientific References

1. Pyo HK, Yoo HG, Won CH, et al.. The effect of tripeptide-copper complex on human hair growth in vitro Archives of pharmacal research; 2007. PMID 17703734 doi:10.1007/BF02978833
2. Pickart L. The human tri-peptide GHK and tissue remodeling Journal of biomaterials science. Polymer edition; 2008. PMID 18644225 doi:10.1163/156856208784909435
3. Trapaidze A, Hureau C, Bal W, et al.. Thermodynamic study of Cu2+ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry; 2012. PMID 21898044 doi:10.1007/s00775-011-0824-5
4. Gruchlik A, Chodurek E, Dzierzewicz Z. Effect of GLY-HIS-LYS and its copper complex on TGF-β secretion in normal human dermal fibroblasts Acta poloniae pharmaceutica; 2014. PMID 25745767
5. Pickart L, Vasquez-Soltero JM, Margolina A. GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration BioMed research international; 2015. PMID 26236730 doi:10.1155/2015/648108

Every identifier above is resolved against PubMed, Crossref or ClinicalTrials.gov at build time, and the title returned by the register is compared with the title stored here. A page does not publish if a reference fails to resolve.

Research-Use Information

For in vitro research use only. This material is a laboratory reagent. It is not a drug, food, dietary supplement, or cosmetic and is not for human or veterinary use, including ingestion, injection, or any other administration. No information on this page describes or implies any effect in humans or animals. Sold only to researchers under our Terms of Sale.