ghk-cu copper peptide hair growth mechanisms scientific evidence studies GHK-Cu as a multifunctional copper peptide GHK-Cu for Hair Growth: Before

van der Klaauw et al., "Role of melanocortin signalling in the preference for dietary macronutrients in human beings," Lancet Lond

Label each vial with the compound name, concentration, and reconstitution date

Cancer 119 , 615621 (2018)

human studies report only mild, transient side effects (occasional headache or nausea)

Darber hinaus berichten Anwender von klarerem Denken, gesteigerter Konzentration und weniger mentaler Erschpfung , wenn sie DSIP regelmig nutzen

So on the narrow question does it stop working after N weeks, the honest answer is: no published evidence says it does, and the mechanism actually argues against it