A Dermatologist's Take on the Copper Peptide (GHK Cu) Trend Some people notice their skin looks worse before it improves with GHK Cu. This temporary phase is often called the copper uglies., #skincare, #ghkcu, #skinhealth, #longevity, #peptides The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline