AHK-CuWhat the studies show

Almost everything written about AHK-Cu traces to one paper. In 2007, a group at Seoul National University tested AHK-Cu on human hair in the laboratory, in two ways: whole hair follicles taken from scalp and kept alive in organ culture, and dermal papilla cells, the cluster at the base of each follicle that drives its growth cycle ¹. Follicles exposed to AHK-Cu grew longer over the culture period than untreated ones, and dermal papilla cells multiplied more. The paper also reports that the cells released more vascular endothelial growth factor, a signal that recruits blood supply, and less transforming growth factor beta-1, a signal that pushes a follicle into its resting phase, and that markers of programmed cell death fell ¹. It is a coherent story — more grow signal, less stop signal, fewer dying cells — told entirely in a dish.

The numbers in the paper are percentages over untreated controls in cultured tissue, and they belong to that setting. A follicle in organ culture has no blood supply, no immune cells and no scalp, and growth over a week or two of culture says nothing about hair counts on a head.

GHK-Cu has the longer record. In 1988, human skin fibroblasts grown with GHK-Cu made more collagen in proportion to the amount added ³. In 1993, GHK-Cu applied to the skin of mice enlarged follicles and lengthened the growth phase of the hair cycle, in a study that used minoxidil as the comparison ⁴. A 2018 review collects wound studies in five animal species and small cosmetic trials of creams in people ². None of that has been repeated with AHK-Cu. The 2007 paper is the only peer-reviewed study of AHK-Cu on hair, and there is no published study of it on collagen, wounds or skin in any animal or person. Products that list AHK-Cu tend to borrow the GHK-Cu literature; the two are different molecules, and a one-amino-acid change in a three-amino-acid peptide is a third of the molecule.

There is no animal study and no human study of AHK-Cu, so nothing is known about what happens if it is applied to skin or injected: whether it is absorbed, whether any of it reaches a follicle, how long it lasts, or whether copper delivered this way has effects of its own. Copper is a biologically active metal, GHK-Cu's own literature attributes some of its effects to the copper rather than to the peptide, and that question has not been asked of AHK-Cu ². It is not an approved drug for anything, and it has no safety record, favourable or otherwise, because no one has looked.