Exhibit 05 · Research doses, not a regimen
GHK-Cu research dosing context: concentrations, routes, and half-life
What was administered to which models at which concentrations and by which routes — a study log, with the human pharmacokinetics gap marked in plain hand.
How GHK-Cu has been dosed in studies
GHK-Cu research-dosing figures span cell culture, topical formulation, and rodent systemic work — and none of them is a human regimen. In human fibroblast cultures, collagen synthesis responded across 10^-12 to 10^-9 M, with onset at 10^-12 to 10^-11 M and a peak near 10^-9 M [1]. Topical cosmetic and clinical formulations sit at roughly 0.05% to 2% (w/w) in creams, serums, and gels [3]. The human hair-loss RCT used a 5-ALA + GHK complex at 50-100 mg/mL topically [4].
The span between those numbers is the first thing to notice. The in vitro collagen response is picomolar-to-nanomolar — vanishingly small concentrations — while the topical and hair-trial figures are formulation percentages and milligrams-per-milliliter applied to a surface, not a circulating dose. They are not convertible into one another, and neither converts into a systemic human dose [16]. Everything on this page is research-context framing: what was administered to which model by which route. It is not a recommendation, and the validated systemic human numbers that a dosing recommendation would require do not exist.
Rodent systemic dosing in the literature
Rodent systemic studies used intraperitoneal, intranasal, and oral routes at model-specific doses. Reported examples include alternate-day intraperitoneal dosing in a mouse pulmonary-emphysema model, 20 mg/kg oral gavage daily in a mouse DSS-colitis model, and 15 mg/kg intranasal dosing in aging and cognition mouse work [16]. These are species-and-model-specific experimental doses.
The gap between these and any human protocol is the point: rodent studies used copper loads below the roughly 35 mg/kg ion-toxicity threshold, but no validated human pharmacokinetic data exist to translate any of it into a human dose. The site's position is to report the research doses and decline to convert them.
GHK-Cu half-life and clearance research
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 IV dosing, and secondary literature cites a short systemic elimination half-life on the order of 1-2 hours, with the copper chelate more stable than free GHK [16]. Topical application instead forms a dermal copper depot — about 97 ug/cm^2 retained over 48 hours — giving prolonged local availability without relying on systemic circulation [5].
Routes studied and topical delivery
GHK-Cu has been studied topically (creams, serums, liposomes, nano-lipid carriers, ionic-liquid microemulsions, wound dressings and hydrogels, nanofibers), intraperitoneally and intranasally in rodents, by oral gavage in rodent colitis, and intravenously or subcutaneously in rodent pharmacokinetic studies [16]. Topical is the route with the human safety record.
Delivery is the limiting factor. Free GHK is highly hydrophilic (clogP -2.24), which restricts passive stratum-corneum penetration; palmitoylation (Pal-GHK, clogP ~1.14), liposomal encapsulation, ionic-liquid microemulsions, and microneedle pretreatment improve it, with a 2025 review reporting about 134 nmol of GHK permeating with microneedling versus none through intact skin [16]. The research-dose context here is delivery science, summarized for general readers.
Stability and the blue-violet color check
The GHK-Cu complex has a very high copper stability constant (log K ~16.4), far higher than free GHK, and is most stable near pH 5-6.5 at a 1:1 copper-to-peptide ratio [7]. The blue-violet color of a reconstituted solution is the expected Cu(II) d-orbital absorption and indicates an intact complex; brown or green shifts indicate oxidation or precipitation [6]. Strong reducing agents — ascorbic acid below about pH 3.5 — reduce Cu(II) and break the complex, and AHAs, BHAs, and low-pH actives can destabilize it or compete for copper [16]. The color check is the simplest at-a-glance integrity signal the literature offers.