GHK Cu A GHK Cu face serum appears blue because the active ingredient, GHK Cu (copper peptide), is naturally a blue colored powder, meaning its inherent color transfers to the serum when mixed in; this blue hue A GHK Cu face serum appears blue because the active ingredient, GHK Cu (copper peptide), is naturally a blue colored powder, meaning its inherent color transfers to the serum when mixed in; this blue hue Can You Mix Retatrutide With GHK Cu? Risks and UK Guidance Bolt Pharmacy GHK Cu Dosage and Protocol: A Medical Provider's Guide to the 30 Day Cycle Perfect B Alibaba.com: GHK Cu Peptides Cosmetic Grade, Fast Delivery, Skin Care Powder Serum : Connect with verified suppliers offering CE, BV, ISO certified products for bulk orders.