GHK-Cu topical vs injectable (UK research): concentrations, handling, and evidence gap

GHK-Cu (glycyl-L-histidyl-L-lysine copper) has two very different literatures. Human cosmetic and skin-repair studies use topical formulations at 0.05–0.2% (Pickart & Margolina, 2018). Injectable protocols in rodents use 1–3 mg/kg subcutaneous doses in wound and hair-follicle studies.

The evidence gap matters: there are no completed randomised trials of injectable GHK-Cu in humans for skin, hair, or systemic outcomes. UK researchers extrapolating from topical human data to injectable protocols are making a jump the literature does not support.

Handling is unusually fragile. GHK-Cu oxidises quickly if agitated; the reconstituted vial should be swirled, not shaken, and stored refrigerated in an amber vial. Full handling and U-100 syringe unit tables for 50 mg and 100 mg vials are in the GHK-Cu dosage UK guide, with mechanism context in the GHK-Cu vs copper peptides comparison.