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Explore  /  AHK-Cu (Copper Tripeptide-3)
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AHK-Cu (Copper Tripeptide-3)

C
lead outcome
Hair-follicle elongation /…
grades vary by outcome ↓
Peptide
also called — AHK-Cu · L-alanyl-L-histidyl-L-lysine copper (Ala-His-Lys + Cu²⁺) · "Copper Tripeptide-3" · a copper peptide "for hair." INCI: as named. High-volume search: "AHK-Cu vs GHK-Cu."
hair appearance (cosmetic)scalp(reference:) dermal papilla / anagen-phase biology

Cosmetic copper-carrier peptide — for hair (vs GHK-Cu's skin focus). Two honest points define this page: (1) its evidence is essentially one ex-vivo/in-vitro study, not a human trial; and (2) "hair growth" claims are medicinal (drug territory, like minoxidil) — a cosmetic can only speak to appearance.

In brief

AHK-Cu is a copper-binding tripeptide engineered for hair (whereas GHK-Cu targets skin). Its evidence is essentially one foundational ex-vivo/in-vitro study (Pyo 2007) showing it stimulates hair-follicle elongation and dermal-papilla-cell proliferation in the lab — but there is no robust human trial showing a topical AHK-Cu serum actually increases hair density in people, and "hair growth" is a medicinal claim (the space occupied by drugs like minoxidil and finasteride). It is a cosmetic ingredient; appearance claims only.

Legal standing, by region
European Union
a cosmetic ingredient in topical hair products (EU Regulatio

a cosmetic ingredient in topical hair products (EU Regulation (EC) 1223/2009; US cosmetic law). But note: hair-growth / anti-hair-loss claims are medicinal — a product making them would be treated as an (unlicensed) drug, not a cosmetic. No injectable lane. Sellable as a cosmetic only with appearance-level claims.

Evidence, by outcome
How we grade →

An honest grade per outcome — drawn from the evidence, not any catalogue. Hype and undemonstrated marketing claims grade low.

OutcomeEvidence base · effectGrade
Hair-follicle elongation / dermal-papilla-cell proliferation (in vitro / ex vivo)
Ex vivo / in vitro only; a single foundational study; a lab effect is not a clinical effect
Pyo 2007 (Arch Pharm Res) — cultured human follicles + DPCs · Genuine stimulation; anti-apoptotic (↑Bcl-2/Bax); ↑VEGF, ↓TGF-β1
C
Topical serum increasing hair density in people (the marketed use)
The lab signal doesn't establish a clinical serum effect; penetration to the dermal papilla from a serum is doubtful (enhanced-delivery methods like microneedling perform better)
No robust human RCT of an AHK-Cu serum · Not demonstrated
D
"Regrows hair / treats hair loss"
Not shown for a cosmetic serum — and it is a drug claim (cf. minoxidil / finasteride)
None (cosmetic) · Not demonstrated
F
Safety (topical)
No hormonal effects (unlike finasteride); suitable for both sexes; long-term data lacking
Broad cosmetic use · Well tolerated; hormone-neutral
—
Disclosure

Vallydia sells its own cosmetic serums, and some ingredients graded here belong to the same categories as those products. Grades are drawn from the published evidence by the method we publish, and applied to our own ingredients on the same terms — our copper-peptide serum is graded no more kindly than the peptides it competes with. We disclose the interest so you can weigh it.

Trade names shown here (for example Matrixyl, Argireline, Syn-Ake) are the property of their respective owners and are used only to identify the ingredient under discussion. Their appearance implies no affiliation with, or endorsement by, the proprietor.

Evidence changes

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We track new research and update these grades as the evidence moves. Leave your email and we'll tell you if the evidence for AHK-Cu (Copper Tripeptide-3) changes - nothing else.

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Cosmetic claims boundary
✓ Allowed (appearance / feel)
  • for **fuller-, thicker-looking** hair
  • healthier-**looking** hair and scalp.
✕ Not allowed (medicinal)
  • grows / regrows hair
  • treats / prevents hair loss
  • stimulates hair follicles
  • increases hair density / count
  • extends the anagen phase

The medicinal-sounding science stays in the reference section; product copy speaks only to appearance/feel (Reg 655/2013). Different fields, never merged.

Identity

a synthetic copper-binding tripeptide (3 amino acids + Cu²⁺; < 40 aa → peptide), structurally like GHK-Cu (#26) but with alanine instead of glycine at position 1. Unlike GHK-Cu, it does not occur naturally in the body — it was engineered specifically for hair/scalp applications (GHK-Cu is skin-focused; AHK-Cu is hair-focused).

Development & history

  • Designed as a synthetic copper-peptide analog optimised for hair-follicle activity. The foundational (and essentially only pivotal) study is Pyo HK et al., Archives of Pharmacal Research, 2007 (PMID 17703734), which established its effects on cultured follicles and dermal papilla cells.
  • Commercialised in hair/scalp serums, frequently combined with GHK-Cu (skin/anti-inflammatory) for a multi-pathway "copper peptide" product. Only ever a cosmetic/research ingredient — never a drug.

Mechanism (as proposed)

a copper-binding tripeptide that, in vitro/ex vivo, stimulates dermal papilla cell proliferation and reduces their apoptosis (↑Bcl-2/Bax, ↓caspase-3), raises VEGF (follicular blood supply), lowers TGF-β1 (delaying catagen), and engages Wnt/β-catenin (the anagen switch). Most of this is lab-based; in-vivo topical relevance is constrained by skin/scalp penetration, and the dose-response is biphasic ("more is not better").

Related reading

What copper peptides are, and how the hair-focused AHK-Cu differs from skin-focused GHK-Cu, in what are copper peptides. Where copper peptides rank among the cosmetic peptides by evidence: cosmetic peptides ranked by evidence. How AHK-Cu's in-vitro evidence stacks up against the rest of a hair serum's ingredients — and where "growth" quietly becomes "support": do hair growth serums actually work?.

Scan your productSee if AHK-Cu (Copper Tripeptide-3) is in what you're usingOpen the scanner →
Chemical identifiers

Cross-reference identifiers for the authoritative external databases — not a recipe, and nothing about how to use it.

PubChem CID168431292
InChIKeyDTNUNAICWDULHO-UVEFGIHYSA-L
SMILESC[C@@H](C(=O)[N-][C@@H](CC1=CNC=N1)C(=O)N[C@@H](CCCCN)C(=O)[O-])[NH-].Cl.[Cu+2]

via PubChem exact-name match (AHK-Cu) · high confidence

Sources — 3 cited
01Pyo HK, Yoo HG, Won CH, et al. The effect of tripeptide-copper complex on human hair growth in vitro. Arch Pharm Res. 2007;30(7):834–839. (PMID 17703734) — the foundational ex-vivo/in-vitro study.
02Copper-peptide hair reviews (2025–2026) — noting enhanced-delivery (microneedling) results and the lab-vs-clinical gap.
03Pickart L, et al. — GHK / copper-peptide grounding (for the class).
Updated 2026-07-13

Grades reflect the published evidence, not our interest. No dosing, reconstitution, or administration is published for research compounds — that restraint is deliberate.

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This site provides neutral scientific reference and sells only products lawful in your region. Nothing here is medical advice, a recommendation, or an offer to supply unapproved medicines. No dosing or administration is published for research compounds. Cosmetic peptides per Regulation (EC) 1223/2009. Unapproved injectable peptides are neither sold nor advertised in the EU (Directive 2001/83/EC, Title VIII). © 2026 Vallydia.