GHK Cu Side Effects, Complications, and Risk Profile Rejuvenation and Youth with GHK Cu Peptide Treatment Dr. Ahmet zyigit The GHK Cu pen works. But needles at home were never the answer. We took the same clinically backed copper peptide complex and put it into a serum you can use in 30 seconds, For a GHKCu (coppercomplexed glycylhistidyllysine) solution prepared at 1 mg mL, how many insulinsyringe units (1 unit = 0.01 mL) should be drawn for a specific dose?