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 Neurogan Copper Peptide Hair Scalp Serum for Fuller Softer Shinier Hair Walmart.com The Pretty Purple Peptide with Powerful Benefits That gorgeous blue purple solution isn't just for looksit's GHK Cu, one of the most studied peptides in regenerative medicine. Here's what it can do for Amazon.com: Copper Peptides GHK Cu Hydra Serum with Hyaluronic Acid Facial Serum for Tightening, Collagen Support, Renewing, Elasticity & Smooth Youthful Looking Skin (30ml 1fl.oz) : Beauty & Personal Care