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 PHOTOS: Gil Hanse designed West Palm Golf Park to open to public Retatrutide Treatment in West Palm Beach, FL Blue Skies Health & Wellness Clinic Peptide GHK CU Cream Concierge MD A Major Shift in Peptide Regulation Is Underway 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