PDF) GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration NL GHK Cu (TETRAPEPTIDE + CU) Synthagen Synthagen PL GHK Cu, is a naturally occurring copper peptide already found in the body Sometimes referred to as Botox in a bottle. , As we age, our natural levels of it declinewhich is why its often Peptide Therapy for Anti Aging and What the Science Actually Supports