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 Copper, Collagen, and Controversy: Inside the GHK Cu Buzz Frontiers Exploring the beneficial effects of GHK Cu on an experimental model of colitis and the underlying mechanisms PDF) Regenerative and Protective Actions of the GHK Cu Peptide in the Light of the New Gene Data