Exposure notes
GHK-Cu half-life and experimental amounts
Where the intact complex goes in a human body remains unmeasured. Study concentrations and rat metabolism describe narrower questions.
The rat metabolism experiment
Endo, Miyagi and Ujiie used high-performance liquid chromatography to follow GHK and HK in rat plasma. After intravenous administration, free GHK was rapidly metabolized to the smaller peptide HK. The experiment followed the copper-free tripeptide in rats. It supplies evidence of rapid degradation under those conditions, with a human half-life for GHK-Cu still unmeasured.
A measured human concentration-over-time record would clarify this question; familiar short half-life estimates in secondary accounts cannot supply it. No validated human GHK-Cu dataset here supplies that record. Copper binding offers a chemical basis for greater stability, but the size of the change in human systemic exposure needs direct measurement.
Study concentrations
The numbers below describe different experiments. Concentration is the amount of a substance in a specified quantity of liquid or material. It leaves the total amount reaching a person or tissue dependent on the rest of the experiment.
| Preparation and setting | Reported study figure |
|---|---|
| GHK around cultured lung fibroblasts | 10 nanomoles per liter |
| GHK-Cu topical creams, gels and serums | Roughly 0.05–2% by weight |
| ALAVAX scalp combination in the 45-man trial | 50 and 100 milligrams per milliliter |
| GHK-Cu scaffold-coating solution in a cell experiment | 1 millimole per liter |
The scalp study combined GHK with 5-aminolevulinic acid. The scaffold experiment grew human fibroblasts on a material outside the body. I see these entries as descriptions of what researchers prepared; converting them into a personal injection amount would require evidence they never supplied.
Copper retained after 48 hours
The human-skin penetration study reported copper retained in the dermis at 97 micrograms per square centimeter over 48 hours. The tissue had been removed from the body, and the measured substance was copper. The finding supports interest in local availability while leaving intact-peptide survival and human blood exposure as different measurements.
Those observations require a linking experiment before they can describe one measure of exposure. A local tissue measurement and a systemic metabolism experiment have different starting materials, settings and endpoints. Joining them would require another experiment.
Human exposure measurements still needed
A useful systemic study would measure the copper-bound complex, its breakdown products, blood concentrations over time and the tissues reached. Repeated exposure would add questions about copper handling and longer-term outcomes. The current research provides no validated human pharmacokinetic basis for a GHK-Cu dose or schedule.
A modest human exposure study could settle more of my doubts than another list of proposed benefits. The cell, animal and topical findings give reasons to investigate. They leave the practical timing of a human systemic treatment unresolved.