GHK CU TB 500 BPC 157 KPV BLEND PEPTIDE (50MG 10MG 10MG 10MG) 80MG VIAL UMBRELLA Labs Can You Use GHK Cu Peptides with Vitamin C Serum? Expert Guide 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 GHK Cu Pre mixed Pen Express Peptides GHK CU BPC 157 TB 500 Blend (GLOW Mix) Lumin Peptides