GHK Cu, BPC 157 & TB 500: Tissue Repair Peptides 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 100mg Peptide Research Use Only Nextech Labs 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 Copper Peptide ~ 1 gram~USA SAME DAY SHIPPING BEST PRICE AND QUALITY eBay