GHK Cu Peptide The benefits, side effects, and more [2026] GHK Cu Topical vs Injection Which is the Better Copper Peptide Form? Peptide GHK CU Cream Concierge MD Why is the injection site painful after administering GHK Cu (Glycyl L Histidyl L Lysine Copper) 2mg mixed with normal saline? If your GHK injection site gets irritated try this , 1. Dilute it by adding more water to the syringe , 2. Let it sit until it reaches room temperature , Also, make sure youre rotating injection