K4 Elite
K4 Elite
AHK-Cu is a copper-binding tripeptide (Ala-His-Lys complexed with Cu(II)) studied in ex vivo human hair follicle and cultured dermal papilla cell models, where published work reports effects on cell proliferation and on VEGF and TGF-beta1 output.
AHK-Cu, catalogued in cosmetic ingredient nomenclature as copper tripeptide-3, is a synthetic tripeptide of alanine, histidine and lysine coordinated to a copper(II) ion. It is a close structural relative of the better-known GHK-Cu, differing only at the first residue, where alanine replaces glycine.
The histidine imidazole and the N-terminal amine form the principal copper coordination site, the same general arrangement described for GHK-Cu. The alanine methyl group slightly alters lipophilicity and coordination geometry relative to the glycine-containing analogue.
The published research base is considerably smaller than that for GHK-Cu and is concentrated on ex vivo human hair follicle organ culture and cultured dermal papilla and dermal fibroblast models. This entry summarises that literature for research reference only.
Copper-binding tripeptides are described in the literature as copper carriers that deliver Cu(II) in a coordinated, redox-buffered form. Copper is a cofactor for lysyl oxidase and for superoxide dismutase, which is the usual mechanistic framing for the extracellular-matrix and antioxidant observations reported for this peptide class.
In the dermal papilla cell work, investigators reported increased cell proliferation, elevated vascular endothelial growth factor (VEGF) secretion, reduced transforming growth factor beta-1 (TGF-beta1) secretion, and a shift in apoptosis markers toward cell survival. The authors proposed that follicle elongation observed in organ culture followed from proliferation of dermal papilla cells together with reduced apoptosis in that compartment.
Human hair follicle organ culture (Pyo HK, et al., Arch Pharm Res, 2007). Model: ex vivo cultured human hair follicles plus cultured human dermal papilla cells. Measure: hair follicle elongation, dermal papilla cell proliferation, growth-factor secretion, apoptosis markers. Reported outcome: AHK-Cu at concentrations from 10^-12 to 10^-9 M stimulated follicle elongation ex vivo and dermal papilla cell proliferation in vitro; the authors proposed that the effect followed from papilla cell proliferation together with reduced apoptosis [1][2].
Dermal fibroblast culture. Model: cultured human dermal fibroblasts. Measure: proliferation, VEGF secretion, TGF-beta1 secretion. Reported outcome: the tripeptide-copper complex increased fibroblast proliferation and VEGF production while decreasing TGF-beta1 secretion in the reported conditions [1][2].
Comparative copper-peptide chemistry. Model: physicochemical characterisation. Measure: copper coordination geometry and stability constants relative to GHK-Cu. Reported outcome: the alanine-for-glycine substitution alters lipophilicity and coordination geometry while preserving the histidine-anchored copper-binding motif [3][4].
Note on the evidence base: the primary follicle and papilla-cell findings trace largely to a single 2007 research group, and independent replication in the peer-reviewed literature is limited. Status is recorded here as emerging research for that reason.
Combinations examined in the research literature. Descriptive only — not a recommendation to combine compounds.