# GHK-Cu research dosing context — concentrations, routes, half-life, and formulation > The concentrations and routes used in published GHK-Cu research: picomolar to nanomolar in vitro, microgram-per-gram rodent IP, percent-w/w topical cosmetic formulations, and plasma half-life context. Research framing only. GHK-Cu is not an FDA-approved drug for any therapeutic indication, so there are no labeled human dose ranges to quote. What follows is the dose context reported in the published research, frame by frame — by route, model, and study. ## Concentrations, not recommendations GHK-Cu is not FDA-approved as a drug for any therapeutic indication, so there are no labeled human dose ranges. What this page records are the concentrations and routes used in published research — fibroblast collagen studies run at picomolar to nanomolar concentrations, rodent systemic studies at microgram-per-gram body weight, topical cosmetic formulations at roughly 0.05 to 3 percent by weight. Those numbers belong to specific studies and specific questions, not to a human dosing protocol. The skin-penetration literature notes that the free peptide is highly hydrophilic (clogP around minus two), and topical delivery strategies — liposomes, palmitoylated derivatives, microneedling — are an active area of formulation research precisely because the molecule does not cross intact skin easily without assistance. ## Framing this section This page summarizes the concentrations, routes, and durations used in published GHK-Cu research. It does not recommend a dose. GHK-Cu is recognized as a cosmetic ingredient (INCI: Copper Tripeptide-1) and is widely used in topical skincare; it is not FDA-approved as a drug for any therapeutic indication, and injectable GHK-Cu was placed on the FDA 503A interim Category 2 compounding list and removed without progression to Category 1. Research-context numbers are best read as study attributes, not as protocols. 'Picomolar in fibroblast culture' describes the dose Maquart used to observe a doubling of collagen synthesis [1]. 'Microgram per gram intraperitoneal' describes the dose Zhang used to observe attenuation of cigarette-smoke-induced emphysema in mice [11]. Neither sentence is a recommendation. A second framing note. The GHK-Cu literature does not converge on a single 'effective concentration' the way an FDA-approved drug label might. The dose-response window in vitro spans six orders of magnitude across published papers — picomolar for fibroblast collagen synthesis, micromolar for Connectivity Map gene-expression screens — and the topical and systemic literatures live on their own scales entirely. Reading the numbers below in that context is the point: each one belongs to a specific model and a specific question. ## In vitro concentrations Fibroblast and dermal-papilla cell work has converged on a narrow window. Maquart 1988 reported collagen-synthesis stimulation beginning at 10^-12 M and saturating around 10^-9 M [1] — that is, picomolar to low-nanomolar concentrations. Pyo 2007 used nanomolar tripeptide-copper in cultured human follicular dermal papilla cells and observed increased proliferation and longer in vitro hair shafts [7]. The Connectivity Map gene-expression work used 1 microM as the standardized screening concentration [8][9][10][14] — roughly three orders of magnitude above the collagen-stimulation threshold and chosen for signal strength in the screen rather than for biological realism. ## Topical cosmetic formulations Cosmetic-grade topical formulations of GHK-Cu typically run from 0.05% to 3% w/w in serum, cream, or eye-area products. The 2024 multicenter cosmetic study after fractional laser resurfacing used 0.05% GHK-Cu gel and reported approximately 25% faster epithelial recovery and roughly 30% lower IL-1beta and TNF-alpha in the GHK-Cu arm during the first 72 hours post-procedure [recent studies summary]. The 2002 Leyden 12-week facial cream study did not standardize concentration in the abstract but reported improvements in laxity, clarity, fine lines, density, and thickness in 71 women using twice-daily application [15]. The 2024 lipid-nano-carrier serum trial used twice-daily application for eight weeks in 40 women aged 40 to 65 and reported a 55.8% reduction in wrinkle volume and a 32.8% reduction in wrinkle depth by profilometry [17]. Formulation pH matters more than concentration alone. The copper(II) chelation is stable in a roughly neutral-to-slightly-acidic window; strongly acidic vehicles (low-pH vitamin C serums, certain exfoliating acids) can perturb the chelation and free the copper, which is one reason cosmetic protocols frequently separate GHK-Cu application from L-ascorbic acid application in time of day. The 2025 liposomal-delivery review highlights this and several adjacent measurement issues — standardized permeation-quantification methods are still lacking, and product-to-product comparison is therefore harder than the percentage on the label suggests [19]. ## Wound-bed and rodent systemic dosing Rodent wound and systemic studies cover a wider dose range. The Maquart 1993 rat wound-chamber paper used nanomolar GHK-Cu infused locally and reached 396% of control collagen content at day 18 and 538% at day 22 [3]. The Canapp 2003 rat ischemic open-wound study used a topical gel and reported a 64.5% area reduction at day 13 versus 28.2% in controls [4]. The Wang 2017 mouse scald-wound study used topical liposomal GHK-Cu and observed faster closure, increased CD31+ vasculature, and increased proliferation markers [20]. The Zhang 2022 emphysema study used intraperitoneal GHK-Cu in C57BL/6J mice at 0.2, 2, or 20 microg/g body weight per day, dosed on alternate days for twelve weeks [11]. The dose range was chosen to bracket the threshold at which Nrf2 / Keap1 antioxidant induction became measurable; all three doses reduced emphysematous morphology and lowered IL-1beta and TNF-alpha in bronchoalveolar lavage. ## Plasma half-life and route considerations Free GHK-Cu has a short plasma half-life. Reported values range from minutes — consistent with rapid aminopeptidase cleavage of the N-terminal glycine — up to roughly 30 to 60 minutes after subcutaneous administration in animal models. Detectable serum levels typically fall below threshold within six to eight hours. Reconstituted aqueous GHK-Cu is reported stable about 28 days refrigerated and light-protected. The combination of short half-life and hydrophilic chemistry constrains formulation. The dominant delivery strategies in the current research literature are liposomal and lipid-nano-carrier encapsulation [17][19][20], palmitoylated derivatives (Pal-GHK), and microneedle or iontophoresis pretreatment of skin [18]. Routes that have been studied at least in research models include topical (the cosmetic primary route), topical to wound bed, subcutaneous (research animals), intraperitoneal (rodent systemic models), intranasal (early Alzheimer's-model exploratory work), and transdermal via microneedle or iontophoresis. ## Common cosmetic co-formulation context The cosmetic literature frequently pairs GHK-Cu with other actives. Hyaluronic acid is a common co-formulation for hydration and extracellular-matrix support, with no known pharmacological interaction. Matrixyl 3000 (palmitoyl tripeptide-1 / palmitoyl tripeptide-7) appears alongside GHK-Cu in many anti-aging products, with the rationale being complementary collagen-signaling pathways. AHK-Cu (alanyl-histidyl-lysine copper), the sister copper tripeptide, sometimes appears in scalp serums where the hair-follicle stimulation evidence base is the draw. Retinoids and GHK-Cu are typically applied at different times of day in cosmetic protocols — the underlying mechanisms are complementary (retinoic acid pathway versus GHK gene-expression pathway) but the vehicle chemistries do not always co-exist comfortably. These are observations about how formulators combine ingredients, not research-tested stack recommendations. The independent-active studies — Maquart's fibroblast work, the Mulder ulcer trial, the Leyden facial cream study, the Badenhorst lipid nano-carrier serum — were single-active or single-formulation, and the cleanest mechanistic evidence sits at the single-active end of that range. ## Regulatory and translation context Two regulatory notes that condition any dose conversation. First, GHK-Cu is not FDA-approved as a drug for any therapeutic indication; cosmetic use of Copper Tripeptide-1 is well established, but therapeutic use remains investigational. Second, injectable / systemic GHK-Cu was placed on the FDA 503A interim Category 2 compounding list and was removed without progression to Category 1, which means it is not currently eligible for 503A pharmacy compounding. Athletes should note that, while GHK-Cu is not currently listed by name on the WADA Prohibited List, listings change and current WADA documentation should be consulted before use. A translation note. The systemic dose ranges that show up in rodent papers (the Zhang 0.2 to 20 microg/g intraperitoneal protocol, for example) do not have a corresponding labeled human equivalent, because no labeled human use of injectable GHK-Cu exists. Cross-species dose extrapolation is not a substitute for clinical-trial data, and the absence of large randomized human therapeutic trials is the single most consequential gap in the GHK-Cu file. --- An archivist's digest of the published literature — not a clinic, not a vendor, not a prescription.