Skin, collagen and copper peptides

GHK is a naturally occurring tripeptide that binds copper with high affinity. Its research profile centres on extracellular matrix biology: stimulation of collagen and glycosaminoglycan synthesis, modulation of metalloproteinase activity, antioxidant behaviour through the copper complex, and gene-expression changes described in cultured fibroblasts. Topical human studies in dermatology report improvements in skin firmness, density and appearance of fine lines, which places GHK-Cu unusually high on the evidence ladder for this category. Systemic effects, by contrast, remain preclinical. The lesson generalises: route of administration is part of the evidence claim. A compound can be well supported topically and unproven systemically, and those two statements should never be blurred.