GHK-Cu (Copper Tripeptide-1)

Identity a tripeptide (3 amino acids: glycine, L-histidine, L-lysine, < 40 aa → peptide) coordinated with a copper(II) ion. Occurs naturally in human plasma, saliva and urine; plasma levels decline ~60% between ages ~20 and ~60. First described by Loren Pickart (1973). ## Development & history - Discovered by Loren Pickart in 1973: he identified a factor in human plasma that made aged liver tissue synthesise proteins like younger tissue — that factor was GHK, which binds copper as GHK-Cu (reported in Nature).

• Over the following decades it was studied primarily for wound healing and tissue remodeling (including some clinical wound-care use), then migrated into cosmetics as Copper Tripeptide-1, commercialised first by Pickart's own company (Skin Biology) and later by many brands.
• Today the topical form is a mainstream cosmetic ingredient; the injectable/systemic form remains a research compound with no approval. ## Mechanism (as proposed) a copper-binding tripeptide that, in vitro, stimulates fibroblast collagen/elastin synthesis (Maquart 1988), modulates MMP/TIMP balance (orderly remodeling), acts as an antioxidant and anti-inflammatory (lowers IL-6/TNF-α), and is pro-angiogenic (VEGF); bioinformatic analyses report broad gene-expression modulation. Most of this is in vitro; in-vivo topical relevance is constrained by poor skin penetration.