GHK-Cu has been studied across collagen, hair follicle, wound healing, and gene-expression research for five decades.

The short version

GHK-Cu is a copper-bound tripeptide the body makes naturally — plasma levels peak around age 20 and fall by more than half by age 60. In fifty years of research it has been studied for collagen production, wound healing, hair follicle biology, and gene expression across a broad range of cell and animal models, with a handful of small human trials.

Topically, it is a legal cosmetic ingredient (INCI name: Copper Tripeptide-1) with the most controlled human evidence behind it of any peptide in its category. Injectable and systemic use is unapproved and has no validated human pharmacokinetic data.

This site organizes the published literature — what the studies actually measured, with every number cited. It does not recommend doses or protocols. For the research evidence on real-world effects and safety considerations, see the effects page.

What Is GHK-Cu (Copper Tripeptide-1)?

GHK-Cu (Copper Tripeptide-1) is a naturally occurring complex of the tripeptide glycyl-L-histidyl-L-lysine chelated to a copper(II) ion. Found in human plasma, saliva, and urine, GHK-Cu was first isolated by Loren Pickart in 1973 from a fraction of human plasma that showed measurable tissue-restorative activity. Its INCI name is Copper Tripeptide-1; its CAS number is 89030-95-5; its molecular weight is 340.38 Da.

The tripeptide sequence GHK corresponds to residues 1-3 of the alpha-2(I) chain of type I collagen — meaning the body releases GHK naturally as collagen degrades at wound sites. The copper(II) ion is not decoration: it is required for activity. Fibroblast studies show that the tripeptide alone — without copper — does not replicate MMP-2 stimulation ^[2].

Plasma concentrations of GHK fall from approximately 200 ng/mL at age 20 to 80 ng/mL by age 60, a decline that parallels age-associated reductions in skin collagen density and tissue-repair capacity ^[4].

For GHK-Cu hair growth research, copper peptide skin benefits, and the full mechanistic picture, see the dedicated pages.

What Does GHK-Cu Do?

GHK-Cu operates at the intersection of structural repair and gene regulation. At picomolar-to-nanomolar concentrations it stimulates dermal fibroblasts to produce collagen, elastin, and proteoglycans, while simultaneously modulating matrix metalloproteinases (MMP-2, MMP-9) and their inhibitors (TIMP-1, TIMP-2) to maintain balanced extracellular-matrix remodeling ^[1][2].

The copper component is particularly consequential. Copper(II) activates lysyl oxidase — the enzyme that cross-links collagen and elastin fibers to give connective tissue its mechanical strength. It also enables superoxide dismutase-mimetic antioxidant activity, reducing oxidative stress in challenged cells ^[4].

Beyond the structural role, GHK-Cu modulates gene expression at scale. A microarray analysis of human cell models found GHK influences approximately 4,000 genes — roughly 31% of the human genome — with 59% upregulated (including collagen, decorin, VEGFR2, and antioxidant pathways) and 41% downregulated (including pro-inflammatory cytokines) ^[4]. This is not a single-target molecule; it is a signaling molecule with a broad footprint.

Primary research areas include: skin collagen and elastin stimulation, wound healing acceleration, GHK-Cu hair growth research, anti-inflammatory gene modulation, and neuroprotective gene expression support.

GHK-Cu Research Areas

The peer-reviewed literature on GHK-Cu spans five research domains:

Skin and collagen. Human clinical studies show GHK-Cu improved collagen production in 70% of treated volunteers at 12 weeks, outperforming vitamin C and retinoic acid comparators in the same study ^[5]. A separate double-blind trial in 40 subjects (aged 40-65) found twice-daily topical GHK-Cu reduced wrinkle volume more than a vehicle control and a comparator peptide control at 8 weeks ^[3]. For copper peptide skin benefits see the dedicated page.

Hair follicle biology. A randomized controlled trial in 45 men with androgenetic alopecia found topical GHK-Cu spray yielded +71.5 additional hairs per cm² vs. +9.6 for placebo over 6 months ^[7]. A 2023 mouse model study found a copper-peptide ionic liquid microemulsion initiated anagen onset at 6 days vs. 9 days for commercial minoxidil ^[8]. See GHK-Cu hair growth research for the full analysis.

Wound healing. Multiple in vivo models show GHK-Cu accelerates wound closure with denser collagen remodeling and VEGF-driven angiogenesis. A 2025 hydrogel study achieved >95% infected wound closure by day 12 vs. ~65% for untreated controls ^[16]. A 2025 comprehensive review confirmed 83–96% wound closure in fibroblast scratch assays at 12–24 hours with GHK nanoparticle formulations ^[17].

Gene expression. The Pickart-Margolina 2018 genomics paper identified GHK as modulating expression of 4,000 human genes, including upregulation of 31 anti-aging gene clusters, suppression of fibrinogen-beta (475%), and an 87% reduction in iron release from ferritin ^[4]. A companion 2017 paper identified 408 neuronal genes upregulated, with 47 DNA-repair genes and 16 antioxidant genes among them ^[11].

Systemic models. In C57BL/6J mice exposed to chronic cigarette smoke, GHK-Cu at 0.2–20 microg/g/day (intraperitoneal, alternate days) reduced pulmonary emphysema morphological changes, suppressed IL-1beta and TNF-alpha, and upregulated the Nrf2/Keap1 antioxidant pathway ^[12].

For the GHK-Cu mechanism of action and full peer-reviewed references, see the dedicated pages.

Frequently Asked Questions About GHK-Cu

GHK-Cu is not FDA-approved as a drug for any indication. As Copper Tripeptide-1 (INCI name), it is a legal cosmetic ingredient in topical products in the US, EU, and UK. Injectable GHK-Cu falls outside FDA-approved indications and is not approved for compounding under 503A/503B for most uses.

For GHK-Cu dosage in research protocols, GHK-Cu side effects, and frequently asked questions about GHK-Cu, see the dedicated pages.