What does the name mean?
The three linked amino acids in GHK belong to the same family of molecules that proteins are made from. GHK-Cu is that chain holding copper. Copper Tripeptide-1 is a name you may see in a cosmetic ingredient list.
Topical means applied to the skin. A review of topical GHK research discusses wrinkle findings and a practical problem: getting the peptide through the skin's outer barrier. The finished formula matters, even when the ingredient sounds familiar.
Getting through skin isn't the same as improving it
In an experiment with human skin outside the body, researchers measured copper passing through and remaining in skin layers. That helps explain delivery. It doesn't tell you what a particular serum will do to your skin over months.
The review brings together earlier research. It isn't a fresh trial of every product with GHK-Cu on its ingredient list. An interesting ingredient still needs evidence about the formula being discussed.
The injection claim needs a separate answer
The skin findings here don't establish that injecting GHK-Cu is effective or safe. A different way of giving a substance needs its own evidence. Familiarity with a skin ingredient can't fill that gap.
The FDA flags possible immune reactions to injectable GHK-Cu. Clumps of peptide and impurities are among its concerns. It also says human safety information is limited. Those are reasons for caution, not a measured rate of harm.
The comparison page brings this question alongside the other topics. When a claim travels, the way the substance was used needs to travel with it. This page gives no injection method or amount.