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, NL GHK Cu (TETRAPEPTIDE + CU) Synthagen Synthagen PL Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives Rejuvenation and Youth with GHK Cu Peptide Treatment Dr. Ahmet zyigit