AHK-Cu (Copper Tripeptide-3)

What Is AHK-Cu?

AHK-Cu is the copper(II) complex of L-alanyl-L-histidyl-L-lysine, a tripeptide that differs from the better-known GHK only in its first amino acid. In GHK the N-terminal residue is glycine; in AHK it is alanine, which adds a single methyl group. The complex is also referred to as copper tripeptide-3.

Researchers have studied AHK-Cu as a tripeptide-copper complex in the context of hair growth.^[1] It belongs to the same family of small copper-binding peptides as GHK-Cu, but it has a much smaller research record.

Peer-reviewed data on AHK-Cu are limited. Only one study found in PubMed as of October 2026 examined AHK-Cu directly, and no animal or human studies of it were identified. Findings on GHK-Cu should not be assumed to apply to AHK-Cu.

Chemical Structure and Molecular Identity

AHK-Cu consists of the three standard L-amino acids alanine, histidine and lysine, coordinated to one copper(II) ion. PubChem (CID 168431292) describes the complex as a monohydrochloride, [L-alanyl-N-L-histidyl-N,N3-L-lysinato(2-)]copper monohydrochloride, with the molecular formula C15H24ClCuN6O4- and a molecular weight of 451.39 g/mol.

The systematic name indicates that copper is bound by nitrogen atoms from the peptide backbone and from the histidine imidazole ring. The peptide keeps a free N-terminal amine on alanine and a free C-terminal carboxylate on lysine.

Key identifiers

• PubChem CID: 168431292
• CAS number: 682809-81-0
• InChIKey: DTNUNAICWDULHO-UVEFGIHYSA-L
• Synonyms: AHK-Cu, copper tripeptide-3, Ala-His-Lys copper

What the Published Literature Covers

The published literature on AHK-Cu consists of a single 2007 laboratory study on human hair follicles and dermal papilla cells.^[1] Dermal papilla cells are specialized fibroblasts that are important in the formation and growth of hair follicles.^[1]

Hair follicle and cell findings

• Ex vivo: AHK-Cu stimulated the elongation of isolated human hair follicles.^[1]
• In vitro: AHK-Cu stimulated the proliferation of cultured human dermal papilla cells.^[1]
• Apoptosis markers: at the highest concentration tested, AHK-Cu raised the Bcl-2/Bax ratio and reduced cleaved caspase-3 and PARP. The number of apoptotic cells fell, but the decrease was not statistically significant.^[1]

The authors proposed that AHK-Cu promotes hair follicle growth by stimulating dermal papilla cell proliferation and preventing their apoptosis.^[1] In their background, they described tripeptide-copper complexes as growth factors for differentiated cells that stimulate dermal fibroblast proliferation and VEGF production.^[1]

No in-vivo animal studies, controlled human trials or safety studies of AHK-Cu were found. Its pharmacology, stability and skin penetration have not been characterized in peer-reviewed work.

With so little published data, researchers typically confirm AHK-Cu identity and copper content using HPLC and mass spectrometry certificates of analysis.

With so little published data, researchers typically confirm AHK-Cu identity and copper content using HPLC and mass spectrometry certificates of analysis.

Regulatory and Research Status

AHK-Cu is not approved by the FDA as a drug for any indication. With one ex-vivo and in-vitro study in the peer-reviewed record, it remains an early-stage research compound.

AHK-Cu is supplied as a research chemical for laboratory use. Because it is closely related to GHK-Cu, it is sometimes discussed alongside that compound, but the two are distinct molecules with separate identifiers and evidence bases.