GHK-Cu is a naturally occurring peptide (sequence Gly-His-Lys) that powerfully influences gene expression. Upon binding copper, the GHK-Cu complex enters cells and acts as a signaling molecule. In the skin, it activates fibroblasts to produce collagen, elastin, and glycosaminoglycans, which are the building blocks of firm, elastic skin. It simultaneously upregulates tissue inhibitor of metalloproteinases (TIMPs) that prevent collagen breakdown, thereby remodeling skin damage. In hair follicles, GHK-Cu stimulates dermal papilla cells to secrete growth factors and prolongs the anagen phase of hair growth. It has been shown to enlarge hair follicles and prevent follicle miniaturization (a common issue in androgenetic alopecia). Additionally, GHK-Cu promotes the release of vascular endothelial growth factor (VEGF), leading to increased blood vessel formation in treated areas. This improved microcirculation aids both skin rejuvenation and hair growth by supplying more nutrients and oxygen. The peptide’s anti-inflammatory and antioxidant actions further protect tissues from damage (for example, it reduces free radical levels and can even assist in nerve regeneration). Together, these mechanisms explain GHK-Cu’s diverse benefits in cosmetic and therapeutic applications.