# Doctor GHK-Cu — A faded-photograph archive of the copper-tripeptide literature > A notebook-style overview of GHK-Cu (copper tripeptide-1): what it is, where it comes from, what the literature has actually shown across five decades of in vitro, animal, and cosmetic-clinical work. GHK-Cu was first isolated from human plasma in the 1970s, where its concentration drops with age — a quiet fact that has anchored most of what followed. This site is an editorial archive of the research, frame by frame. ## The short version GHK-Cu is a small copper-binding tripeptide that occurs naturally in human blood. Its concentration in plasma falls roughly threefold between age 20 and age 60 — a quiet fact that has shaped most of the research that followed. In the cosmetic world it is known as Copper Tripeptide-1 and is widely used in anti-aging serums and creams; in research settings it is also studied for wound healing, lung repair, hair follicle biology, and gene expression. Topical cosmetic use has a long, largely uneventful track record. Injectable and systemic use is a different matter — it is unapproved, has no human pharmacokinetic data, and is experimental. This site is an editorial archive of the published literature: what each study actually used, what each study actually measured, and what remains to be shown. For a fuller picture of what researchers and cosmetic users report, [the effects page](/effects) is the next frame to open. ## What GHK-Cu is GHK-Cu is a complex of three amino acids — glycine, L-histidine, and L-lysine — bound to a single copper(II) ion. The free tripeptide weighs about 340 Daltons; the copper-loaded form picks up the metal at high affinity through the imidazole nitrogen of histidine and the alpha-amino nitrogen of glycine, with a peptide carbonyl completing the chelation site. In the cosmetic-ingredient register the same molecule answers to Copper Tripeptide-1, INCI's standardized label. It is endogenous. Loren Pickart first isolated GHK from human plasma in the early 1970s while studying why young serum supported hepatocyte function in culture better than old serum did. Plasma concentration falls roughly threefold across adulthood — a quiet number that has shadowed nearly every interpretation of the literature since. Whatever GHK-Cu is doing biologically, the human body keeps less of it as we age, and most of the research that followed reads as a long attempt to ask whether that drop matters. ## What the literature has shown Most of what is known sits in three drawers. The first is in vitro: cultured fibroblasts respond to GHK-Cu at picomolar to low-nanomolar concentrations by roughly doubling collagen synthesis [1], and the same dose range shifts the small-proteoglycan profile (decorin, dermatan sulfate, heparan sulfate) toward organized rather than scar-type deposition [2]. The second drawer is animal models — rat wound chambers infused with GHK-Cu show collagen content reaching 396% and 538% of control at days 18 and 22 [3], topical gel more than doubles the rate of ischemic open-wound closure in rats [4], and intraperitoneal GHK-Cu attenuates cigarette-smoke-induced emphysema in mice while raising Nrf2-axis antioxidant defense [11]. The third drawer is human, and it is smaller. A 1994 multicenter randomized trial of topical GHK-Cu gel on diabetic neuropathic ulcers reported 98.5% median area closure versus 60.8% for vehicle [5]. A 2002 facial-cream study in 71 women showed improvements in skin laxity, clarity, fine lines, density, and thickness over twelve weeks [15]. A 2024 lipid-nano-carrier serum trial in 40 women reported a 55.8% reduction in wrinkle volume and a 32.8% reduction in wrinkle depth over eight weeks [17]. Large randomized FDA-registered systemic trials are not in the drawer. ## Why this site exists Search the open web for GHK-Cu and the signal is uneven. Marketing copy stacks on top of forum threads, which sit on top of press releases, which paraphrase Pickart's review articles in turn. The underlying papers are mostly there to be read — they are just rarely linked, and even more rarely quoted with the dose, species, and route attached. Doctor GHK-Cu is an independent editorial archive of the published literature on this molecule. Each section is summarized from a real paper. Each numbered chip in the margin is a citation. The 'doctor' in the name is shorthand for archivist — a quiet darkroom curator of the file, not a treating physician. ## Where to read next If you are new to the molecule, start at /research for the mechanism overview and the chronological tour of the literature. If you want the numbers — picomolar fibroblast doses, microgram-per-gram rodent IP doses, percent-w/w topical cosmetic formulations, plasma half-life — /dosage is the frame to open. /faq answers the questions the search logs see most often, including the regulatory ones. /references holds the full sortable index of every paper cited across the site, with DOIs and PubMed or PMC links beside each entry. /about explains what this archive is and is not. --- An archivist's digest of the published literature — not a clinic, not a vendor, not a prescription.