The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline Rejuvenation and Youth with GHK Cu Peptide Treatment Dr. Ahmet zyigit GHK Cu is a small copper bound peptide (glycyl histidyl lysine with a copper ion) found naturally in human tissues and fluids. Its levels decline with age, and it plays a role in tissue repair, regeneration, GHK Cu, commonly known as copper peptides, are found naturally within the human body where they play a vital role in skin repair and maintenance. Copper peptides support optimal skin function by helping