Peptide class
Peptides with high affinity for copper ions that act as biological copper carriers, modulating gene expression, collagen synthesis, and wound healing through copper-dependent enzymatic pathways.
| Compound | Mechanism | Primary Use | Profile |
|---|---|---|---|
| GHK-Cu (Copper tripeptide-1) | Copper chelation and delivery; activates wound-healing gene networks, collagen and elastin synthesis, antioxidant | Wound healing, skin regeneration, anti-aging, hair growth research | View profile |
| AHK-Cu (Copper tripeptide-3) | Copper chelation; dermal papilla cell proliferation; anti-apoptotic effects; VEGF upregulation; extracellular matrix remodelling | Hair follicle stimulation, scalp health, dermal repair research | View profile |
Two current members. Both are copper-binding tripeptides sharing the histidine and lysine residues, differentiated by their N-terminal amino acid.
Copper is an essential trace element and cofactor for numerous enzymes including lysyl oxidase (critical for collagen cross-linking), superoxide dismutase (antioxidant), ceruloplasmin, and cytochrome c oxidase (mitochondrial electron transport). Copper peptides act as biological delivery vehicles, chelating copper ions and transporting them to sites of cellular demand more efficiently than free copper ions, which are poorly absorbed and potentially cytotoxic at elevated concentrations.
GHK (Glycine-Histidine-Lysine), initially identified in human plasma by Pickart in the 1970s, exerts biological effects beyond simple copper delivery. Research by Pickart and colleagues has demonstrated that the GHK sequence itself, with or without copper, can modulate gene expression, activating wound-healing gene networks through interaction with transcription factors including SP1. GHK-Cu has been shown to upregulate genes associated with collagen (COL1A1, COL3A1), elastin, decorin, and vascular endothelial growth factor (VEGF), while downregulating genes associated with inflammation and cellular senescence.
GHK-Cu stands apart from other peptides discussed on this site in having substantial topical research alongside injectable research. As a tripeptide with a molecular weight of approximately 340 Da (excluding copper), it has favourable skin penetration characteristics, making it a common active ingredient in cosmetic anti-aging formulations. Topical GHK-Cu research has investigated wound healing acceleration, post-procedural skin recovery, and hair follicle stimulation. Injectable research contexts examine systemic and targeted delivery of the compound.
GHK was first isolated from human albumin by Loren Pickart in 1973, where it was identified as a plasma-borne growth hormone-stimulating factor. Subsequent research identified its copper-binding affinity and wound-healing properties. Over 50 years of GHK research has produced a substantial literature on collagen synthesis, wound healing, antioxidant activity, and, more recently, anti-aging gene expression modulation.
The large-scale gene expression analyses of GHK-Cu published in the 2010s (Pickart et al., 2012) examined its effects across thousands of genes, finding modulation consistent with tissue remodelling, anti-inflammatory, and anti-senescence pathways. Research has investigated GHK-Cu for its potential role in chronic wound healing, skin aging, COPD (where GHK levels are commonly reported to be depleted), and hair loss.
GHK-Cu (Copper tripeptide-1)
The prototypical and most extensively researched copper peptide. Naturally occurring in human plasma at concentrations that decline with age, from approximately 200 ng/ml in young adults to below 80 ng/ml in older adults. Research has investigated its potential role in wound healing acceleration, skin rejuvenation, collagen synthesis, and hair follicle cycling. Available as both an injectable research compound and a cosmetic ingredient.
AHK-Cu (Copper tripeptide-3)
A synthetic copper-binding tripeptide and structural analogue of GHK-Cu, differing only in the N-terminal amino acid: alanine in AHK-Cu versus glycine in GHK-Cu. This single substitution increases copper-binding affinity relative to GHK-Cu and produces a more focused activity profile centred on dermal papilla cells and hair follicle biology. Unlike GHK-Cu, AHK-Cu is not endogenous; it is a wholly synthetic research compound classified as Copper Tripeptide-3 under INCI nomenclature. Research has investigated AHK-Cu for hair follicle stimulation, dermal papilla cell proliferation, and angiogenesis support via VEGF upregulation. It is not FDA-approved for any indication and is used primarily in topical scalp formulations, often in combination with GHK-Cu.