GHK Cu: The Peptide That Supports Healthy Aging GHK Cu (copper peptide) is naturally occurring in the body and plays a role in supporting skin health, collagen production, and tissue repair. As GHK Cu Peptide: What It Does for Body Composition and Metabolic Health GHK Cu Engage Peptides Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance[v3] Preprints.org The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance[v3] Preprints.org