GHK Cu vs NAD+: Which Longevity Peptide Should You Take or Stack? Defy GHK Cu (glycyl L histidyl L lysine) is a naturally occurring copper binding peptide found in human plasma. As levels decline with age, so may its support of the biological processes involved in collagen production, skin What Is GHK Cu and What Does It Do? Bubolo Medical Advanced GHK Cu Neck & Face Serum Premium Quality Neurogan Health 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