# GHK-Cu Dosage in the Research Literature (Concentrations and Routes)

> GHK-Cu dosage as documented in research: picomolar-to-nanomolar in vitro, ~0.05–2% topical formulations, intraperitoneal and oral rodent ranges, and the pharmacokinetic gap. Research-context framing only.

The concentrations and routes the studies used — in cell culture, in topical formulations, and in rodent models — with the human pharmacokinetic gap marked plainly. Research context, never a usage instruction.

## How the literature records GHK-Cu dosage

GHK-Cu dosage in the research literature is reported as study concentrations and routes, not human doses, and this notebook keeps it that way: it describes what was administered to which model, and it does not recommend any human regimen. The defining in-vitro range is picomolar-to-nanomolar — fibroblast collagen synthesis begins between 10⁻¹² and 10⁻¹¹ M and peaks near 10⁻⁹ M [1], and the COPD-fibroblast gene-reversal work used 10 nM [8]. Topical cosmetic and clinical formulations run roughly 0.05% to 2% (w/w) in creams, serums and gels [13]. These are the [GHK-Cu dosage in research](/dosage) figures the rest of the notebook cites; none is a dose for a person.

## Concentrations and routes studied

Rodent systemic studies used intraperitoneal dosing across a wide range: a bleomycin pulmonary-fibrosis model administered 2.6, 26 and 260 µg/mL/day on alternate days from day 4 to 21, with dose-dependent suppression of fibrosis and inflammation [7]. A 2025 colitis model used 20 mg/kg by oral gavage daily [14]. The controlled human hair study applied the ALAVAX 5-ALA + GHK complex topically at 50 and 100 mg/mL [4]. Routes documented in the literature span topical (cream, serum, liposome, nano-lipid carrier, wound dressing and nanofiber), intraperitoneal, intranasal, oral gavage, and intravenous or subcutaneous in pharmacokinetic studies [6][13]. The breadth of routes reflects how much of the record is preclinical.

## Pharmacokinetics and the half-life gap

No rigorous human pharmacokinetic half-life has been published for GHK-Cu. The free tripeptide (340.38 Da) is rapidly cleared by plasma peptidases — a rat HPLC study documented rapid metabolism of GHK to the dipeptide HK after intravenous dosing [16]. Secondary literature cites a short systemic elimination half-life on the order of 1–2 hours, with the copper-chelated complex more stable than free GHK [9]. Topical application changes the picture locally: it forms a dermal copper depot, with about 97 µg/cm² retained over 48 hours, giving prolonged local availability even as systemic clearance is fast [5]. The absence of validated human Cmax, bioavailability and tissue-distribution data is the central pharmacokinetic gap the notebook flags.

## Model doses by research context

The concentrations and routes vary by what each study was modeling, and reading them side by side shows how preclinical the record still is. In skin and matrix work, the active range is picomolar-to-nanomolar in fibroblast culture [1] and roughly 0.05–2% (w/w) in topical formulations [13]. In the anti-inflammatory and fibrosis models that anchor this notebook's lens, the bleomycin pulmonary-fibrosis study dosed 2.6, 26 and 260 µg/mL/day intraperitoneally on alternate days [7], and the 2025 colitis study used 20 mg/kg by oral gavage daily [14]. The COPD-fibroblast gene-reversal experiment used 10 nM in culture [8]. Tissue-engineering studies coated or conjugated the peptide rather than dosing systemically — GHK-modified alginate was non-cytotoxic from 1–500 ng/mL [11], and a scaffold coating used 1 mM GHK-Cu [12]. The one controlled human protocol, the ALAVAX hair trial, applied 50 and 100 mg/mL of a 5-ALA + GHK complex topically to the scalp [4]. None of these is offered here as a human dose; they are the figures the studies reported, listed so the record can be read honestly.

## Stability and handling notes from the record

The GHK-Cu complex is most stable near pH 5–6.5 at a 1:1 copper-to-peptide ratio, and its high stability constant (log K ~16.4) limits pro-oxidant free-copper release [9]. The blue-violet color of a reconstituted solution is the expected Cu(II) absorption and indicates an intact complex, whereas brown or green shifts indicate oxidation or precipitation [9]. Strong reducing agents — ascorbic acid below ~pH 3.5 — reduce Cu(II) and break the complex, and AHAs, BHAs and other low-pH actives can destabilize it or compete for copper [13]. Free GHK is highly hydrophilic (clogP -2.24), which limits passive stratum-corneum penetration; palmitoylation, liposomal encapsulation and microneedle pretreatment are the delivery strategies the literature evaluates to improve it [13]. There is no FDA- or EMA-approved therapeutic GHK-Cu product by any route [3].

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A hand-bound studio notebook of the GHK-Cu copper-peptide literature — every collagen, gene, and hair-count clipping pasted in and sourced to its paper, the honest gaps left in the margin, with nothing here prescribed, dispensed, or for sale.