Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms GHK Cu vs NAD+: Which Longevity Peptide Should You Take or Stack? GHK Cu as a multifunctional copper peptide: synthesis routes, process engineering and emerging applications Systems Microbiology and Biomanufacturing Springer Nature Link The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Does GHK Cu Really Work? 40 Years of Research Reviewed