The effect of tripeptide-copper complex on human hair growth in vitro

This Korean study, conducted by Kyu Han Kim's group at Seoul National University, was one of the first peer-reviewed works to systematically characterize AHK-Cu (alanyl-histidyl-lysine copper) — the cosmetic analog of Pickart's original GHK-Cu — as a stimulator of human hair growth. The context was the search for topical alternatives to minoxidil and finasteride in alopecia management, especially for cosmetic use.

The researchers used two complementary models: ex vivo human hair follicle cultures (maintained viable in culture medium) and isolated human dermal papilla cells (DPCs), which are the mesenchymal component regulating the hair cycle. AHK-Cu was tested at different concentrations, with morphological evaluation of follicles, cell proliferation assays (BrdU), and apoptosis markers (TUNEL, Bax/Bcl-2).

Results were positive across all parameters: AHK-Cu significantly stimulated hair follicle elongation ex vivo (effect comparable to minoxidil), increased DPC proliferation in a dose-dependent manner, and at the optimal concentration of 10⁻⁹ M reduced the number of apoptotic DPCs, modulating proteins involved in the intrinsic apoptotic pathway (increased Bcl-2, decreased Bax). These effects support maintenance of the anagen (growth) phase of the hair cycle.

This work provided the first robust mechanistic evidence for the use of AHK-Cu in cosmeceutical anti-hair-loss formulations, positioning it as an alternative to GHK-Cu with potentially superior hair tissue affinity. Although not a human clinical trial, the ex vivo/in vitro data were extensively cited in subsequent literature and underpinned the inclusion of AHK-Cu in professional hair serums.