AHK-Cu

DCosmetic ingredient; no clinical evidenceTissue-repair peptides →copper tripeptide AHKAla-His-Lys copperalanyl-histidyl-lysine copper
In one paragraphAHK-Cu is a copper-bound tripeptide — alanine, histidine, lysine — marketed for hair growth in serums and, increasingly, as an injectable alongside GHK-Cu. The entire evidence base is one 2007 laboratory study in which it lengthened human hair follicles kept alive in culture and made dermal papilla cells divide. No trial has applied it to a person's scalp, let alone injected it. It is a legal cosmetic ingredient and nothing more; GHK-Cu, by contrast, has small human trials for topical skin use.
Schematic 3D structure of AHK-Cu
3 residues · Ala-His-Lys bound to a copper ion · schematic
Overall gradeD No human evidence
Human trials0 — one ex vivo follicle study
Outcomes graded4
Last reviewed10 September 2026
EvidenceWhat it isHow it worksUnknownsMolecule & PKRegulationQuestionsReferences

What the human research shows

The comparison with GHK-Cu is the point of this page: same copper, same 'peptide' marketing, and a hundredth of the evidence. Nothing here is human.

MetabolicCardioMuscleHealingNeuroImmuneSexualSkinAgeing

Evidence profile0–5

  • Metabolic & weight—0.0
  • Cardiovascular—0.0
  • Muscle & growth—0.0
  • Healing & repair—0.0
  • Neuro & sleep—0.0
  • Immune & inflammation—0.0
  • Sexual & hormonal—0.0
  • Skin & appearanceD0.0
  • Ageing & longevity—0.0
No benefit outcome for AHK-Cu has both human evidence and a measurable effect, so the profile is empty. That is the finding, not a gap in the chart.
OutcomeGradeEffect sizeHuman studiesWhere the evidence comes from
Hair growth (topical, in people)DNo human evidenceNot measurable0 controlledNo human trial of any design. The single study kept plucked human follicles alive in a dish for a week and measured elongation.12
Hair follicle elongation (ex vivo)DNo human evidenceNot measurable1 laboratory studyAt nanomolar concentrations AHK-Cu lengthened cultured human follicles and increased dermal papilla cell proliferation; the anti-apoptotic effect it was designed to show was not statistically significant. Laboratory evidence, not clinical.1
Injected use (skin, hair)DNo human evidenceNot measurableNoneNo study of any kind. An injected copper peptide has no established pharmacology in humans.
Safety in humansadverseDNo human evidenceNot measurableCosmetic-use experience onlyTopical use as a cosmetic ingredient has no reported safety signal; injected use has no data at all.
AMultiple good human trials, consistentBSome human trials, mostly consistentCFew or weak human studiesDAnimal or anecdotal onlyeffect size · red = adverse

Literature searched to 10 September 2026. Human studies only; animal and cell work informs the mechanism section and nothing else.

What it is

AHK-Cu is a synthetic tripeptide chosen for its resemblance to GHK-Cu, the naturally occurring copper-binding peptide found in human plasma. It appears in hair serums and shampoos and, on the grey market, as a lyophilised injectable sold with GHK-Cu as a 'copper peptide stack'.

Unlike GHK-Cu, it has no human trials at all — not for skin, not for hair. Its reputation rests on one ex vivo study and on the halo of its better-studied relative.

How it is thought to work

Proposed, from the laboratory study: stimulation of dermal papilla cell proliferation and vascular endothelial growth factor, and reduced apoptosis. Whether it penetrates skin, reaches follicles, or does anything at all in a living scalp has not been tested.

What is still unknown

  • Whether topical AHK-Cu affects hair in a living person.
  • Anything at all about injected use.

The molecule and how long it lasts

Identity
Formula
C15H24ClCuN6O4-
Molecular weight
451.39 g/mol
CAS number
682809-81-0
PubChem
CID 168431292

PubChem record is the hydrochloride

PubChem record, read 23 September 2026.

Pharmacokinetics
Route
Topical as sold; no human study
Half-life
No human pharmacokinetic data

No pharmacokinetic study in people.

Regulatory status

European Union
Cosmetic ingredient

Permitted in cosmetics; no medicinal authorisation. Injectable products are unauthorised medicines.

United States
Cosmetic ingredient

Sold in cosmetics without drug approval; injectable versions are unapproved drugs.

United Kingdom
Cosmetic ingredient

Same position; injectable use is unlicensed.

Australia
Cosmetic ingredient

Topical cosmetic use permitted; injectables not on the ARTG.

Canada
Cosmetic ingredient

Topical cosmetic use; no DIN for any injectable.

Sport (WADA)
Not named

Not on the Prohibited List.

Questions people actually ask

Does AHK-Cu grow hair?
In a dish, it lengthened cultured follicles in one study. On a person, it has never been tested. That is the whole evidence base.
AHK-Cu or GHK-Cu?
GHK-Cu has small human trials for topical skin use and a much larger laboratory literature; AHK-Cu has one ex vivo study and nothing in people. For injected use, neither has any human evidence.
Is injecting copper peptides safe?
No study has looked. Topical cosmetic use has no known safety signal; injection is a different exposure with no data.

One page per claimed effect

References

  1. 1
    Pyo HK, Yoo HG, Won CH, et al. The effect of tripeptide-copper complex on human hair growth in vitro.Arch Pharm Res, 2007Ex vivo follicles and cultured dermal papilla cells; no human subjects.
  2. 2
    Searches of PubMed and trial registries for AHK-Cu in humans.LYO literature search, September 2026No clinical study identified.

Change log

  • 2026-09-10Initial publication. Grade D: one ex vivo study, no human trial.