What GHK-Cu is

GHK-Cu (also called copper peptide GHK-Cu or copper tripeptide-1) consists of three amino acids — glycine, L-histidine, and L-lysine — coordinated with a copper(II) ion. Discovered in 1973 by Loren Pickart, who identified that human plasma contains a factor that restores aged liver tissue function — that factor was GHK-Cu.

Mechanism of action

GHK-Cu’s most distinctive feature is its breadth of action. Gene expression analyses show it modulates approximately 4,192 human genes — over 30% upregulated, the rest downregulated. Key pathways include:

• Collagen and elastin synthesis — direct stimulation of fibroblast activity
• Antioxidant defense — increases SOD expression, glutathione, and copper-dependent enzymes
• Anti-inflammatory action — downregulates TNF-α and IL-6 pathways
• 5α-reductase inhibition — relevant to androgenetic alopecia
• VEGF expression — angiogenesis and wound healing
• p53 tumor suppressor restoration — relevant to longevity research

Endogenous decline with age

Plasma GHK-Cu measurements show a steep decline:

• Age 20: ~200 ng/mL
• Age 40: ~120 ng/mL
• Age 60: ~80 ng/mL

This roughly 60% decline correlates with reduced wound healing capacity, slower tissue regeneration, and the visible signs of skin aging. Restoring GHK-Cu via topical or injectable application is the basis of most therapeutic applications.

Topical applications — skin

Collagen synthesis

Multiple controlled studies show GHK-Cu serums (typically 1-3 ppm) increase dermal collagen synthesis. A 2007 study compared GHK-Cu to retinoic acid and found GHK-Cu produced significant increase in collagen, elastin, and glycosaminoglycan synthesis.

Wrinkle reduction

A 12-week study of GHK-Cu eye cream showed significant reduction in fine lines and increase in skin density vs vehicle control.

Hair growth applications

GHK-Cu inhibits 5α-reductase (the enzyme converting testosterone to DHT, the primary driver of androgenetic alopecia) and stimulates dermal papilla cell proliferation. Topical formulations (1-3 mg/mL) applied to scalp are studied for both male pattern hair loss and female pattern hair loss.

Wound healing

Original 1980s research established GHK-Cu’s wound-healing properties. Used in some clinical wound care formulations.

Dosing — topical, injectable, microneedling

• Topical serum: 1-3 ppm in cosmetic products; can apply 1-2x daily
• Microneedling delivery: Higher concentrations (0.1-0.5%) delivered through skin barrier
• Subcutaneous injection (research): 1-3 mg per dose, several times per week

Side effects and tolerability

Topical use is very well tolerated; mild redness occasionally reported. Injectable use is studied less in human cohorts but appears well-tolerated in available data.