The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Everyone talks about the glow from GHK Cu Nobody talks about the burn. Yes, GHK Cu gets hyped for tighter looking skin, scar support, collagen support, and regeneration. And the reason people talk about it Acquired Glucocorticoid Resistance Due to Homologous Glucocorticoid Receptor Downregulation: A Modern Look at an Age Old Problem Journal of Neuroscience Research JNR Neuroscience Journal Wiley Online Library Regulation of m Opioid Receptors: Desensitization, Phosphorylation, Internalization, and Tolerance