# GHK-Cu Dosage Research Context — What concentrations and routes have actually been studied > A research-context summary of GHK-Cu dosing: cosmetic topical concentrations (0.05-1 percent w/w), cell-culture nanomolar to micromolar ranges, rodent topical microgram amounts, and the absence of a validated human injectable protocol. Research only — not a dosing recommendation. Concentrations, routes, and half-lives drawn from the published GHK-Cu literature. This page describes what has been investigated in vitro, in animals, and in topical cosmetic clinical work — not a dosing recommendation for any human use. ## The concentrations that have actually been studied The number that matters most depends on the route. For topical cosmetic use — the route with the most human data — copper tripeptide-1 is typically formulated at 0.05 to 1 percent weight-for-weight, the range the Cosmetic Ingredient Review assessed in 2018 as safe at typical concentrations [1]. Below that, cell-culture work used concentrations down to one ten-billionth of a molar to see fibroblast collagen responses [8]. In rodent wound and lung studies, doses were in the low-microgram-per-gram range. For injectable human use, there is no validated protocol — that gap is the honest answer to many of the questions people bring to this compound. This page organizes the concentration record by route, gives the source for each number, and is explicit about where the data runs out. Numbers from community sources are not reproduced here because no peer-reviewed human basis exists for them. ## The numbers that matter, by route GHK-Cu is one of the few compounds in the broader research-peptide conversation that has an established, conventional, regulated route — topical cosmetic application — alongside the more contested ones. The numbers below are taken directly from published studies and from the Cosmetic Ingredient Review record. They are research context, not dosing instructions. **Topical cosmetic formulations** carry copper tripeptide-1 at roughly 0.05 to 1 percent w/w. This is the range assessed by the CIR Expert Panel in 2018 and the range most cosmetic formulations work within [1]. The Finkley 2005 facial trial worked in this range without disclosing the exact percentage; the Miller 2006 post-laser trial used a topical copper tripeptide complex cream without disclosing the concentration; the Yuvan Research 2023 study reported a 21-subject 12-week topical protocol without disclosing the percentage in the press release [20][21][22]. **Cell culture** has used a wide range, deliberately. Maquart's fibroblast collagen work used 1 to 10 nanomolar [8]. Kang's keratinocyte work used 0.1 to 10 micromolar [10]. Campbell's emphysema-fibroblast experiments used 10 nanomolar [17]. Connectivity Map transcriptomic profiling used 1 to 10 micromolar [7]. Effects are biphasic — higher is not always more — and the in-vitro range overlaps physiological plasma concentrations only at the low end. **Rodent topical wound studies** have used low microgram amounts applied to the wound bed [9][15]. Canapp's dog pad-wound work used a 0.4 percent topical gel [14]. Park's mouse acute lung injury work used dose-dependent intraperitoneal administration without specifying a single representative dose in the abstract [16]. Cherdakov's 2010 rat bone-fracture protocol used approximately 140 micrograms per injection over 10 days [28]. **Human injectable dosing** does not have a validated protocol. A 2015 Pickart review offered a theoretical extrapolation suggesting 100 to 200 milligrams systemic equivalent, with the explicit caveat that no controlled human trial has tested this [28]. ## Half-life, stability, and skin penetration Free GHK in plasma is short-lived — minutes to roughly one hour — because of peptidase cleavage. The copper-bound form is more stable, but precise human pharmacokinetic data remain limited [28]. This pharmacokinetic profile is part of why topical and depot delivery have dominated the formulation literature: a systemically administered free peptide is gone quickly, while topical application keeps the compound at the site of intended action. GHK is stable in aqueous solution at pH 4.5 to 7.4 for at least 2 weeks at 60 degrees Celsius [28]. The complex is highly hydrophilic — log D approximately -2.4 — yet, somewhat unusually for a hydrophilic tripeptide, GHK and GHK-Cu have been shown to cross stratum corneum membrane models, which is the empirical basis for taking topical delivery seriously [28]. The Fagron Academy 2025 compounding review walks through stability constraints that compounders specifically work within when preparing topical GHK-Cu formulations [26]. Routes that have actually been studied: topical (the dominant route, across cosmetic and post-procedure clinical work), subcutaneous and intraperitoneal in rodents, intravenous in animal pharmacokinetic work, and conjugated nanoparticle or wound-dressing delivery in newer engineering studies [25][28]. ## What the human clinical record supports, and what it does not The cosmetic topical record supports concentrations in the 0.05 to 1 percent w/w range applied to facial skin over weeks to months, with measurable improvements in skin density, elasticity, fine-line scores, and post-procedure healing endpoints [1][20][21][22]. The CIR 2018 review concluded that copper tripeptide-1 is safe as used in cosmetics at typical concentrations [1]. The veterinary topical record supports 0.4 percent topical gel application for full-thickness wound healing in dogs [14]. Topical research-grade applications in rodents have used low microgram amounts at the wound bed [9]. The injectable record in humans is essentially absent. There is no published controlled clinical trial of injectable GHK-Cu at any indication. Wellness and longevity clinic use of injectable copper peptides is informed by veterinary and preclinical work plus uncontrolled self-reports, not human trials [29]. This gap is the principal reason the FDA has historically scrutinized injectable GHK-Cu on the 503A interim bulks list more cautiously than topical GHK-Cu, and it is the reason injectable concentrations and protocols are not summarized on this page — there is no validated number to report. Formulation research has also looked at combinations: AHK-Cu (a structurally similar copper peptide) for hair-follicle elongation work; matrixyl / palmitoyl pentapeptide-4 in cosmetic peptide pairings; hyaluronic acid as a co-formulated humectant; vitamin C in head-to-head and combination comparisons; and microneedling as a mechanical adjunct, with a 2025 study reporting approximately 26.5 percent hair regrowth metric improvement in a copper-peptide-plus-microneedling protocol [4][20]. These are formulation research observations, not clinical dosing recommendations. --- An independent editorial digest of the published regulatory and research record on GHK-Cu — not legal advice, not medical guidance, not a vendor.