AHK-Cu
Copper-binding tripeptide
A copper-binding tripeptide studied alongside GHK-Cu in dermal and follicular research contexts.
Overview
AHK-Cu is a synthetic copper-binding tripeptide (alanyl-histidyl-lysine complexed with copper) used as a cosmetic ingredient. It is structurally related to GHK-Cu, differing in its first amino acid (alanine rather than glycine).
At a glance
What AHK-Cu does
AHK-Cu (Copper Tripeptide-3) is a synthetic copper-binding tripeptide made of alanine, histidine and lysine complexed with copper(II). It is a close cousin of GHK-Cu but is studied specifically for the hair follicle: its central documented action is stimulating hair-follicle growth and dermal-papilla cell activity. The foundational work — a 2007 ex-vivo study on isolated human hair follicles — showed that AHK-Cu prolonged and elongated the growth (anagen) phase of cultured follicles and increased proliferation of dermal-papilla cells, which are the signaling cells that orchestrate the hair-growth cycle.
Mechanistically, AHK-Cu drives these effects largely through growth-factor signaling. It upregulates vascular endothelial growth factor (VEGF) in dermal fibroblasts and papilla cells, which improves the microvascular supply feeding each follicle, and it down-regulates TGF-β1, a factor that suppresses follicular epithelial growth and is implicated in androgenetic hair loss. As with all copper peptides, the copper ion is functionally important, acting as an enzymatic cofactor. Notably, the growth-promoting effect is concentration-dependent and biphasic: follicle growth was stimulated in the roughly picomolar-to-nanomolar range but inhibited at higher concentrations, so formulation dosing matters.
The evidence is essentially preclinical — human ex-vivo follicle cultures and in-vitro cell work — rather than large controlled clinical trials. It is used almost entirely as a topical cosmetic ingredient in hair and scalp serums (commonly 100–500 ppm), with skin/anti-aging benefits attributed to the same copper-peptide collagen and VEGF signaling shared with GHK-Cu.
Effects reported in research
- Prolonged and elongated the anagen (growth) phase of isolated human hair follicles in ex-vivo culture (2007 study).
- Increased proliferation of dermal-papilla cells, the follicle's growth-controlling cells (in-vitro).
- Upregulated VEGF expression in fibroblasts and papilla cells, improving the microvascular supply around follicles (in-vitro).
- Down-regulated TGF-β1 secretion from fibroblasts — a factor implicated in androgenetic alopecia (in-vitro).
- Growth effect is biphasic/concentration-dependent: stimulatory at picomolar–nanomolar levels, inhibitory at higher concentrations (in-vitro).
- Delivers copper as an enzymatic cofactor, supporting the same collagen/matrix signaling seen with related copper peptides.
- Attributed skin benefits (firmness, matrix support) via copper-peptide collagen signaling shared with GHK-Cu — evidence largely preclinical.
- No large controlled human trials — human evidence is limited to ex-vivo follicle and in-vitro cell studies.
Effects listed reflect findings reported in the research literature — many in animal or in-vitro models. Listing an effect is not a claim of efficacy or a therapeutic indication in humans.
Mechanism of action
Like other copper tripeptides, AHK-Cu binds copper(II) and is used to deliver copper in cosmetic applications. In cosmetic and in-vitro research it has been associated with effects on hair follicle biology and vascular/dermal-related signaling, though its evidence base is smaller than that of GHK-Cu. These properties are drawn from cell and cosmetic studies.
Mechanistic description reflects published research-literature understanding. Much peptide research is preclinical (in-vitro or animal-model); mechanism in humans may differ and is not established for many compounds.
What it's studied for
Research contexts in which AHK-Cu appears in the literature. Listing a research area is not a claim of efficacy or a therapeutic indication.
Key characteristics
- A copper-binding tripeptide closely related to GHK-Cu, with alanine in place of glycine
- Used mainly as a cosmetic ingredient, often in hair-care contexts
- Functions as a copper-delivery peptide
- Has a smaller research base than GHK-Cu
- Studied largely in cosmetic and in-vitro settings
Reported research dosing reference only
Educational reference, not dosing guidance. The figures below summarize amounts reported in published research and research-community protocols, provided for educational and research context only. They are not medical advice, not a recommendation, and not instructions for human use. AHK-Cu is a research compound.
AHK-Cu is used as a topical cosmetic copper peptide, so reported use is a formulation concentration and the literature emphasizes low, precise levels. These are reference figures for research context only, not human dosing guidance.
- Topical scalp/skin formulations described in the low-percentage range (product examples include ~7% liposomal liquids diluted for use)
- Follicle-model activity reported at very low molar concentrations (~10^-12 to 10^-9 M), with inhibition at ~10^-8 to 10^-7 M
Biphasic dose response makes low-concentration targeting important; higher concentrations may be counterproductive.
How it compares
AHK-Cu differs from GHK-Cu by a single amino acid and is more often associated with hair-related cosmetic applications, with a comparatively limited evidence base.
Commonly studied alongside
Compounds frequently researched together with AHK-Cu in the literature. Cross-referenced for research context — not a usage or combination recommendation.
Handling & Stability
Lyophilized peptides are stored cold, protected from light, and reconstituted only at the time of intended in-vitro work.
- Avoid repeated freeze-thaw cycles
- Verify supplier lot and Certificate of Analysis
- Follow institutional lab-safety protocols
Analytical & COA Concepts
Reputable research suppliers publish a third-party Certificate of Analysis per batch. Key analytical concepts referenced in COAs include:
Category Context
AHK-Cu sits in the Cosmetic & Dermal area of the PeptiDex library.
- Entry type: Research compound reference
- Browse the full library →
- Glossary of terms →
Where researchers source AHK-Cu
For researchers studying AHK-Cu, third-party suppliers such as Practically Natty Peptides offer research-grade material with third-party Certificates of Analysis and US-based shipping.
View research-supplier listing →
Outbound link to a third-party research supplier. Inclusion does not constitute endorsement; all editorial content is developed independently.
Frequently asked questions
What is AHK-Cu?
AHK-Cu is a synthetic copper-binding tripeptide made of alanine, histidine and lysine (Ala-His-Lys) complexed with a copper(II) ion, designated copper tripeptide-3. It is studied in cosmetic contexts for hair and scalp as well as skin applications.
How does AHK-Cu differ from GHK-Cu?
Both are small copper-carrying peptides, but AHK-Cu begins with alanine rather than the glycine of the naturally occurring GHK-Cu. AHK-Cu is a fully synthetic analog that has been highlighted specifically for hair-follicle activity, whereas GHK-Cu is the collagen-derived sequence more associated with skin remodeling.
What is AHK-Cu studied for?
Research and cosmetic literature describe AHK-Cu in the context of the hair-growth (anagen) phase, follicle protection, and scalp/skin quality. As with related copper peptides, it is characterized as a signaling ingredient and is not an approved drug for hair loss.
Why does concentration matter so much for AHK-Cu?
Follicle-model research reports a biphasic effect: growth stimulation at very low (picomolar to nanomolar) concentrations but inhibition at higher (roughly 10^-8 to 10^-7 M) concentrations. This means precise low-concentration targeting is emphasized, and higher is not better.
What is the molecular weight of AHK-Cu?
The base copper tripeptide is roughly 354 Da, slightly heavier than GHK-Cu (~340 Da). Some product listings cite higher formula weights that reflect liposomal or salt forms rather than the base peptide-copper complex.
How is AHK-Cu used?
It is typically used topically in serums and scalp sprays and is supplied as a cosmetic-grade powder or pre-made liquid (for example liposomal preparations). It is intended for surface application, not injection.
Answers are educational summaries of research-literature context and do not constitute medical advice. See the Research Library, COA guide, and Storage & Handling guide for more.