F tier · safety concern
There are no human clinical trials of AHK-Cu at all; its published evidence base is essentially one 2007 ex vivo hair follicle paper, and almost everything else attributed to it is borrowed from the separate and much better studied GHK-Cu.
ahk-cu
AHK-Cu is a copper-binding tripeptide marketed largely on the reputation of its structurally distinct cousin GHK-Cu, but its own published record consists of a small number of in vitro and ex vivo experiments. No randomised controlled trial of AHK-Cu in humans appears to have been published for hair or skin outcomes.
// we supply this one
available as a research reagent
≥ 99% HPLC · lyophilised powder · batch certificate published. Grade F above is our own and is not adjusted because we stock it.
the explanation
This is a three-amino-acid molecule that grabs onto copper, sold for hair and skin. Almost all the impressive copper-peptide research you see quoted was done on a different peptide called GHK-Cu, not this one - AHK-Cu itself rests on roughly one lab study from 2007.
regulatory status
Cosmetic ingredient; no drug approval
AHK-Cu is used as a cosmetic ingredient under the INCI designation copper tripeptide-3 and has no drug approval anywhere for hair loss, wound healing or skin ageing. It is not an FDA-approved treatment for androgenetic alopecia; minoxidil and finasteride hold those approvals. Injectable presentations of AHK-Cu are entirely unapproved and outside the cosmetic framework that covers topical use.
how it works · proposed mechanism
The proposed activity is that of a copper-delivery chelate rather than a receptor ligand.
Copper chelation and delivery
The histidine imidazole and terminal amine coordinate copper(II) in a square-planar arrangement, mirroring the way serum albumin and GHK transport copper. Copper is a required cofactor for lysyl oxidase and superoxide dismutase, which is the usual mechanistic argument.
Dermal papilla effects in vitro
In cultured human dermal papilla cells the complex increased proliferation at picomolar to nanomolar concentrations. It also shifted apoptosis markers, raising the Bcl-2/Bax ratio and lowering caspase-3 and PARP signals at 10^-9 M.
Angiogenic signalling claim
Copper tripeptide complexes are reported to elevate vascular endothelial growth factor, which is invoked to explain follicular effects. The quantitative VEGF data in this literature come predominantly from GHK-Cu work rather than AHK-Cu.
what’s reported
evidence shape
4 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
Search results and product pages for AHK-Cu are saturated with GHK-Cu findings presented as if they were interchangeable, which they are not - a different residue at position one is a different molecule with a different copper coordination environment. Strip out the borrowed GHK-Cu citations and what remains for AHK-Cu is a single ex vivo study on follicles from three donors.
key published findings
- Ex vivo human tissue (Pyo et al., Archives of Pharmacal Research 2007, 30:834-839): AHK-Cu at 10^-12 to 10^-9 M stimulated elongation of microdissected human hair follicles and proliferation of cultured dermal papilla cells; the study used 240 follicles from three volunteers.
- In vitro (same study): at 10^-9 M the complex increased the Bcl-2/Bax ratio and decreased the apoptosis markers caspase-3 and cleaved PARP in dermal papilla cells.
- In vitro (copper tripeptide literature generally): tripeptide-copper complexes elevate vascular endothelial growth factor production, though the quantitative dataset is dominated by GHK-Cu rather than AHK-Cu.
- Human trials: no randomised controlled trial of AHK-Cu for hair density, hair count, wrinkle depth or any other clinical endpoint was identified in this review.
- Regulatory: AHK-Cu is registered and used as a cosmetic ingredient (INCI copper tripeptide-3) with no drug indication anywhere.
limitations of the evidence
- The primary evidence is a single small ex vivo and in vitro study from one group, published in 2007 and not independently replicated at scale.
- Effects were seen at picomolar to nanomolar concentrations in culture; whether those concentrations are achieved at the dermal papilla after topical application in intact human scalp is unaddressed.
- Most claims circulating about AHK-Cu are transplanted from GHK-Cu, which is a chemically distinct peptide with its own, larger and partly clinical, evidence base.
documented safety signals
- Copper peptides applied topically are generally well tolerated in cosmetic use, but no formal human safety trial of AHK-Cu specifically has been published.
- Copper-containing preparations carry a theoretical concern about cumulative copper exposure with high-concentration or occlusive use, which has not been quantified for this compound.
- Injectable use is unstudied entirely; delivering a transition-metal chelate parenterally raises metal-handling and local-reaction questions that no published study addresses.
- Contact dermatitis and irritation are reported for copper-peptide cosmetic formulations as a class, usually attributed to the formulation rather than the peptide.
identity
| full name | Alanyl-histidyl-lysine copper(II) complex |
| category | Cosmetic |
| modality | peptide |
| formula | C15H24ClCuN6O4 (copper tripeptide-3 hydrochloride, the commonly supplied salt form) |
| molar mass | 451.39 g/mol |
| cas | 682809-81-0 |
| sequence | Ala-His-Lys (AHK), free tripeptide C15H26N6O4, average mass approximately 354.4, complexed with copper(II) |
laboratory handling
| storage | Supplied as a blue to blue-violet lyophilised powder; suppliers specify cool, dry, dark storage, commonly refrigerated or frozen for long-term. Copper peptide solutions are light- and oxidation-sensitive and lose colour and presumably activity on degradation. |
| solubility | Water-soluble; the copper complex dissolves readily in water and aqueous buffers, and the hydrochloride salt form is the presentation most commonly supplied for cosmetic formulation. |
| co-studied with | AHK-Cu is frequently combined with GHK-Cu in topical products on the reasoning that the two copper tripeptides address hair and skin compartments respectively, but no controlled study has tested that combination against either peptide alone. Treat any AHK-Cu plus GHK-Cu claim as untested. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
4 citedWikipedia (reference overview of the distinct GHK-Cu evidence base) · 2026 · review
Archives of Pharmacal Research, 30:834-839 · 2007 · preclinical
ChemicalBook / BOC Sciences product documentation · 2025 · preclinical
Archives of Facial Plastic Surgery · 2005 · preclinical
others in Cosmetic