Measurement units · Dish vs cream vs rodent
Study doses and GHK-Cu concentrations by model
Why picomolar cell bath numbers and milligram-per-kilogram mouse injections never translate into a human dosing schedule.
Human dosage status and GHK-Cu blood data
Readers routinely mistake laboratory concentration units for medical prescriptions. Neither the United States Food and Drug Administration nor the European Medicines Agency has approved GHK-Cu as a therapeutic drug, and no validated human pharmacokinetic data or approved clinical dosing guidelines exist.
I base my GHK-Cu injection skepticism on Endo's 1997 rat plasma chromatography study, which shows how rapidly blood enzymes cleave the free tripeptide. The authors developed a high-performance liquid chromatography assay with detection limits of 50 nanograms per milliliter for intact GHK and 15 nanograms per milliliter for its metabolite L-histidyl-L-lysine. When GHK entered rat plasma, proteolytic enzymes rapidly snipped off the glycine residue, converting the tripeptide into histidyl-lysine within minutes. That assay measured free GHK rather than copper-complexed GHK-Cu in rat plasma, and no validated human pharmacokinetic or clearance study for GHK-Cu has been published.
Study doses of GHK-Cu versus human blood data
In Tier 4 cell culture papers, researchers express bath concentration in molarity inside liquid media bathing cultured cells. In the 1988 Maquart fibroblast study, collagen synthesis began rising at 10 to the power of minus 12 to 10 to the minus 11 molar and peaked at 10 to the minus 9 molar (one nanomolar). In the 2012 Campbell emphysema lung study, cultured human lung fibroblasts restored collagen contraction at 10 nanomoles per liter. And in the 2025 Hong melanogenesis study, a palmitoyl copper peptide (Pal-GHK-Cu) combined with acetyl tyrosine increased melanin production in human A375 and mouse B16 cell lines in a dose-dependent manner at 0 to 8 micrograms per milliliter.
Natural human blood carries its own baseline concentration of the peptide. Both the 2015 Pickart review and the 2020 Dou and Ladiges W review state that human plasma around age 20 contains roughly 200 nanograms per milliliter of GHK (about 10 to the minus 7 molar), declining to roughly 80 nanograms per milliliter by age sixty. One gram equals a billion nanograms, meaning endogenous plasma measurements represent nanogram-per-milliliter trace amounts in blood.
Topical GHK-Cu trial doses and animal dosing data
Sorting the remaining numbers into topical human trials versus rodent injections prevents dangerous mix-ups:
| Study & year | Species & route | Reported study figure | Key context from the paper |
|---|---|---|---|
| Hostynek et al. 2011 | Excised dermatomed human skin (in vitro chamber) | 97 +/- 6.6 micrograms of copper per square centimeter retained over 48 hours | Measured over 48 hours in excised dermatomed human skin layers. |
| Lee et al. 2016 | 45 men (six-month topical trial) | 50 milligrams per milliliter and 100 milligrams per milliliter | Tested a combined 5-aminolevulinic acid and GHK peptide complex (ALAVAX) over six months; hair counts rose by 71.5 hairs at 50 milligrams per milliliter and 52.6 hairs at 100 milligrams per milliliter versus 9.6 hairs with placebo. |
| Bobyntsev et al. 2015 & Sever'yanova 2017 | Rats (intraperitoneal injection) | Microgram-per-kilogram to sub-milligram-per-kilogram range | Tested bare copper-free Gly-His-Lys in rats, reporting reduced anxiety-like behavior and reduced pain-induced aggressive-defensive attack frequency. |
| Dou et al. 2020 | Aged mice (systemic administration) | 10 to 15 milligrams per kilogram | Reviewed aged-mouse studies reporting improved spatial learning and increased histone deacetylase 2 labeling; scaling rodent milligram-per-kilogram weights directly to human syringes is scientifically invalid. |
Separately, a 2025 topical delivery review reports approximately 134 nanomoles of GHK permeating after microneedle pretreatment versus none through intact skin. Notice how the 2016 scalp trial reported hair-count increases of 71.5 hairs at 50 milligrams per milliliter and 52.6 hairs at 100 milligrams per milliliter versus 9.6 hairs on placebo, while the 1988 fibroblast culture study observed collagen-synthesis stimulation beginning between 10 to the power of minus 12 and 10 to the minus 11 molar with maximum stimulation near 10 to the minus 9 molar. Review our benefits analysis or references for every source link.