AHK-Cu
Published research and evidence base
AHK-Cu (L-alanyl-L-histidyl-L-lysine copper(II), INCI-adjacent to the cosmetic ingredient Tripeptide-3) is a structural analogue of GHK-Cu in which glycine is replaced by alanine. The directly published evidence base is very small: a single ex vivo and cell-culture study of human hair follicles and dermal papilla cells is the principal dermatological source, supplemented by a topical delivery study of Tripeptide-3 for facial sebum and by work on a vitamin C-conjugated AHK derivative in a non-cutaneous model. Most claims made for AHK-Cu are extrapolated from the wider copper-tripeptide literature rather than from AHK-specific data.
- Studies cited
- 10
- Published 2023+
- 6
- Newest paper
- 2026
- Last reviewed
- Aug 2026
Recurring themes in the literature
- dermal papilla cell proliferation
- hair follicle elongation ex vivo
- copper tripeptide analogue chemistry
- VEGF induction
- sebum modulation
- topical delivery of hydrophilic tripeptides
Compound identifiers
- CAS
- 682809-81-0
- PubChem
- 168431292
What AHK-Cu is, chemically.
- Molecular formula
- C15H24ClCuN6O4-
- Molecular weight
- 451.39 g/mol
- CAS number
- 682809-81-0
- PubChem CID
- 168431292
These figures come from the PubChem record for this compound and describe the free base. Lyophilised peptide is normally supplied as an acetate or trifluoroacetate salt and carries residual water, so the mass of powder in a vial is not the same quantity as the molecular weight above would suggest. Chromatographic purity on a certificate of analysis does not resolve that difference either — how to read a certificate of analysis explains why.
10 published studies.
Ordered by strength of study design, then by recency. Every entry links to its source record so the finding can be checked against the paper rather than taken on our word.
- 01Human clinical2024
Microemulsions and Nanoemulsions for Topical Delivery of Tripeptide-3: From Design of Experiment to Anti-Sebum Efficacy on Facial Skin.
Magrode N, et al. · Pharmaceutics · formulation design of experiment plus facial oil-reduction testing on human skin
Hydrophilic Tripeptide-3 was formulated into optimised micro- and nanoemulsions and evaluated for facial oil reduction. The work is primarily a delivery-system study; the human component measured sebum rather than clinical dermatological endpoints.
- 02Animal in vivo1991
The hair follicle-stimulating properties of peptide copper complexes. Results in C3H mice.
Trachy RE, et al. · Annals of the New York Academy of Sciences · C3H mouse hair-growth model
This is the foundational report that peptide-copper complexes stimulate hair follicles in the C3H mouse model, and it is the origin of the copper-peptide hair-growth claim later extended to AHK-Cu. No abstract is held in the PubMed record.
- 03In vitro2026
Copper(II)-Tripeptide Complexes as Potential Skin Healing Agents: Synthesis, Characterization, and Wound Repair Ability.
Aguilar L, et al. · ChemMedChem · synthesis and characterisation of copper(II)-tripeptide complexes with wound-repair assays
Copper(II)-tripeptide complexes were synthesised, characterised and assessed for wound repair ability as candidate skin healing agents. The work addresses the copper-tripeptide class rather than AHK-Cu specifically.
- 04In vitro2018
Vitamin C-linker-conjugated tripeptide AHK stimulates BMP-2-induced osteogenic differentiation of mouse myoblast C2C12 cells.
Jung JI, et al. · Differentiation · mouse C2C12 myoblast cell culture, BMP-2-induced osteoblast differentiation
Vitamin C-linker-conjugated AHK enhanced C2C12 proliferation and BMP-2-induced alkaline phosphatase, Smad1/5/8 phosphorylation and osteoblast gene expression. The paper notes that vitamin C-conjugated tripeptides were originally developed for collagen synthesis and dermal fibroblast growth, but the experiments themselves were osteogenic, not cutaneous.
- 05In vitro2007
The effect of tripeptide-copper complex on human hair growth in vitro.
Pyo HK, et al. · Archives of Pharmacal Research · human hair follicle organ culture (ex vivo) and cultured human dermal papilla cells
AHK-Cu at 10^-12 to 10^-9 M stimulated elongation of human hair follicles ex vivo and proliferation of dermal papilla cells, and 10^-9 M AHK-Cu reduced the proportion of apoptotic dermal papilla cells on annexin V/propidium iodide flow cytometry. This is the primary and essentially the only dedicated dermatological study of AHK-Cu.
- 06Review2026
Overview of Short Peptides for Hair Loss.
Fan C, et al. · Biomedicines · narrative review of short peptides investigated for hair loss
The review surveyed short peptides that mimic intracellular signals as candidate hair-loss interventions, positioning them against approved agents such as minoxidil, finasteride and dutasteride and against transplantation and stem cell approaches.
- 07Review2026
A framework for the safety evaluation of peptides in cosmetics.
Bjerke DL, et al. · Current Research in Toxicology · review of historical cosmetic peptide safety evaluation plus a proposed six-tool bioinformatic framework
The authors reviewed how cosmetic peptides have historically been safety-substantiated and proposed a bioinformatics-based next-generation risk assessment framework, testing it against a panel of peptides including palmitoyl hexapeptide-12 and palmitoyl pentapeptide-4.
- 08Review2025
Exploring the Role of Tripeptides in Wound Healing and Skin Regeneration: A Comprehensive Review.
Adnan SB, et al. · International Journal of Medical Sciences · review of tripeptide wound-healing literature published 2016-2025
The review summarised tripeptide effects on cell migration, proliferation and differentiation, inflammation, angiogenesis and extracellular matrix remodelling in tissue repair. It covers the tripeptide class, within which AHK-Cu is a minor and sparsely studied member.
- 09Review2025
Peptides: Emerging Candidates for the Prevention and Treatment of Skin Senescence: A Review.
Pintea A, et al. · Biomolecules · review of cosmetic peptide classes and stratum corneum permeability strategies
The review classified cosmetic peptides as signal, carrier, neurotransmitter-inhibitor and enzyme-inhibitor peptides, and identified poor membrane permeability as one of the most significant limitations on their delivery and effectiveness.
- 10Review1993
Chemical agents and peptides affect hair growth.
Uno H, Kurata S · Journal of Investigative Dermatology · review of a decade of macaque androgenetic alopecia experiments (minoxidil, diazoxide, 5-alpha-reductase inhibitor, peptides)
The review reported that agents assessed by phototrichogram, folliculogram and follicular DNA synthesis acted by stimulating follicular cell proliferation and enlarging anagen follicles from vellus to terminal type. It situates peptide-copper complexes within the broader hair-growth pharmacology of the period.
What this evidence does not establish.
There are no published human clinical trials of AHK-Cu for hair growth or skin appearance, and no controlled comparison of AHK-Cu against GHK-Cu in any model. The single dermatological study is an ex vivo and cell-culture experiment from 2007; nothing comparable has been published since, and no recent (2023 onward) study addresses AHK-Cu directly. Claims about AHK-Cu efficacy in cosmetic use are therefore extrapolations from copper-tripeptide class data.
Common questions about the research.
- What is AHK-Cu?
AHK-Cu is the copper complex of the tripeptide alanyl-histidyl-lysine. It is studied mainly in hair-follicle and dermal-papilla-cell models, where in vitro work reports increased follicle elongation and papilla-cell proliferation at nanomolar concentrations.
- How does AHK-Cu differ from GHK-Cu?
They are distinct tripeptides that share a copper-binding motif. GHK-Cu has a large literature on collagen synthesis and matrix remodelling; AHK-Cu's much smaller literature centres on ex vivo hair-follicle and dermal-papilla-cell studies. Neither body of work substitutes for the other.
- How strong is the evidence base for this compound?
Thin, and it is worth being direct about that. The core AHK-Cu data are in vitro and ex vivo; controlled in vivo studies specific to this compound are lacking, so class-level copper-peptide findings are often extrapolated to it. Research claims should be weighed accordingly.
- Have any human clinical trials of AHK-Cu been published?
No. There are no published human clinical trials of AHK-Cu for hair growth or skin appearance, and no controlled comparison of AHK-Cu against GHK-Cu in any model. The principal dermatological source remains a 2007 ex vivo and cell-culture study in which AHK-Cu at picomolar to nanomolar concentrations stimulated elongation of human hair follicles in organ culture and proliferation of dermal papilla cells, and reduced the proportion of apoptotic dermal papilla cells. Nothing comparable has been published since, so most claims made for the compound are extrapolations from copper-tripeptide class data.
Available from our catalog
For research purposes only. Not for human consumption, diagnosis, treatment, or prevention of any condition. Nothing on this page is medical advice, and no study summarised here should be read as a recommendation.