doses studied

§ · THE SHORT VERSION

The dose ranges in GHK-Cu research vary enormously depending on the route and the endpoint being studied. In cell culture, fibroblast collagen induction starts at a picomolar concentration (one trillionth of a mole per liter) and peaks at nanomolar. In rodent experiments, intraperitoneal doses have ranged from half a microgram per kilogram for behavioral effects up to 15 milligrams per kilogram for intranasal cognitive studies — a roughly thirty-million-fold spread. Human studies have used topical formulations from 0.05% to 2% in creams and gels. There is no validated human dose for injectable or systemic GHK-Cu: no published pharmacokinetic trial, no established safety window, no approved prescribing reference. Every figure on this page describes what researchers administered in a defined published study — it is a record of the literature, not a dosing guide.

framing — research-context only

GHK-Cu is not approved by the FDA or EMA as a drug for any human therapeutic indication. The cosmetic ingredient classification (Copper Tripeptide-1, INCI) covers topical use only and is a regulatory ingredient designation, not a medical approval ^[1]. Every dose listed below is reported as it appeared in a published study — a description of what researchers administered to cells, animals, or human volunteers under a defined protocol, not a recommendation for human use.

This page is read in the third person. The phrasing is studied at X μg/kg in [species] via [route] — never take X mg/day.

in vitro — picomolar to nanomolar

The foundational dose-response for GHK-Cu sits in cell culture. Maquart and colleagues' 1988 work in FEBS Letters established collagen induction in human dermal fibroblasts beginning at 10⁻¹² M (picomolar) and reaching maximum effect at 10⁻⁹ M (nanomolar) ^[3]. That range has held across three decades of fibroblast and wound-cell work.

The Connectivity Map screen that identified GHK as a 127-gene COPD-signature reverser used the database's standard small-molecule signature concentrations; the validation work in primary COPD lung fibroblasts was conducted at 10 nM and 0.1 nM ^[2]. The Park 2016 LPS acute-lung-injury model used 10 μM GHK-Cu in cell culture ^[11]. The Kang 2012 keratinocyte stemness work used 0.1–10 μM ^[25]. The Min 2024 CNS protein-aggregation study used 0–1000 μM, with effects beginning in the low micromolar range against 0–500 μM Cu/Zn challenge ^[14]. The Hsieh 2020 zebrafish copper-toxicity rescue reported a minimum effective concentration of 1 nM in waterborne exposure ^[21].

The pattern across cell lines is consistent: low nanomolar concentrations are sufficient for gene-modulation and antioxidant effects, with higher micromolar concentrations required to buffer acute metal overload ^[1][14].

intraperitoneal rodent doses

Rodent intraperitoneal dosing in the published literature spans roughly four orders of magnitude depending on the endpoint.

The Bobyntsev 2015 rat behavioral study used 0.5 μg/kg intraperitoneally and reported reduced shock-induced aggression and decreased anxiety-like behavior in elevated plus maze tests ^[15] — the lowest intraperitoneal dose in the recent literature.

The Zhang 2020 bleomycin-induced pulmonary fibrosis study in C57BL/6 mice used 0.2, 2, and 20 μg/g/day (i.e., up to 20 mg/kg if expressed per kilogram of body weight) given every other day intraperitoneally ^[7]. The three-dose escalation showed dose-dependent attenuation of collagen deposition, NF-κB downregulation, and Nrf2 activation.

The Rosenfeld 2023 sleep-deprived aged-mouse cognition study used 15 mg/kg/day for 5 days intraperitoneally ^[16]. Other rodent wound and tissue-repair studies in the literature have used subcutaneous routes at 1–10 μg/kg ^[1].

intranasal — the CNS route

Intranasal administration has emerged as the active CNS research route since 2023. The Tucker 2023 study in 5xFAD transgenic mice used 15 mg/kg intranasally three times weekly for 3 months. The endpoints — reduced amyloid plaques, lower MCP-1 neuroinflammation in the frontal cortex and hippocampus, preserved cognitive performance — established CNS bioavailability and durable preclinical effect at that dose and schedule ^[13].

The intranasal route is significant for translation because it bypasses first-pass metabolism and offers direct nose-to-brain delivery of peptides too short-lived in plasma to be useful by systemic routes. The published plasma half-life of GHK-Cu in rodent pharmacokinetics is on the order of minutes ^[1], which is one reason the intranasal CNS work attracts attention — local delivery near the target tissue avoids the plasma-clearance problem entirely.

topical concentrations — the human record

Topical applications in cosmetic creams and gels have used concentrations of 0.05% to 2% w/w GHK-Cu ^[1]. The 1994 Mulder diabetic foot ulcer trial used 2% GHK-Cu gel (then sold under the Iamin trade name) ^[6]. Cosmetic formulations typically run 0.05% to 0.5%, with delivery-vehicle variations — nano-lipid carriers, liposomes, microneedling — materially affecting penetration through intact stratum corneum ^[1].

The Badenhorst 2016 nano-lipid carrier work used 0.1% GHK-Cu and reported a 31.6% reduction in wrinkle volume over 8 weeks ^[8]. The Leyden 2002 study in 71 women used a daily-application facial cream for 12 weeks at a manufacturer-specified concentration ^[4]. A 2024 IRB-approved trial in 21 women used daily topical gel for 3 months and reported a 28% mean increase in dermal collagen by histology ^[9].

implanted devices and local depots

Several studies have used GHK or GHK-Cu impregnated into a delivery substrate rather than administered as a solution. Arul 2005 used GHK-impregnated collagen wound dressings in streptozotocin-diabetic rats; the dressing acted as a slow-release local depot and produced roughly 9-fold higher wound collagen content versus controls ^[17]. Ahmed 2005 used GHK in collagen nerve-guide tubes implanted into transected rat sciatic nerves, reporting elevated NGF, NT-3, NT-4 and increased axon counts ^[18]. The Kanazawa 2015 ACL reconstruction model used a local GHK-Cu graft soak at the time of surgery ^[19].

Device-bound dosing complicates dose calculation — the relevant pharmacology is local concentration at the wound or graft interface rather than systemic exposure — but the implanted approach addresses the plasma half-life problem the same way intranasal delivery does.

stability and handling — what the literature notes

GHK is stable as a lyophilized powder. Reconstituted GHK-Cu solutions are sensitive to light and oxidation; cosmetic formulations typically use opaque, air-excluding packaging ^[1]. The Cu(II) coordination is what enables the redox-buffered antioxidant behavior — uncomplexed GHK and uncomplexed Cu(II) behave very differently in the same assays ^[1][20]. A 2016 toxicity-biomarker analysis flagged poorly chelated commercial copper formulations as a possible source of skin irritation or oxidative stress when the peptide-to-copper stoichiometry is off ^[1].

The published plasma half-life is short — minutes-order in rodent pharmacokinetics — but the functional biological effect (gene-expression modulation, fibroblast activation, transcriptional shifts) substantially outlasts circulating levels ^[1]. This is consistent with a signal-triggered transcriptional response rather than a sustained receptor-occupancy model.