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 The House Kitchen & Bar + The Cabana West Palm Beach Restaurants NAD+ and GHK Cu aren't interchangeable! They're complementary One restores what's happening beneath the surface: cellular energy, mental clarity, vitality that lasts beyond a caffeine rush. The other rebuilds what you see: Whitening GHK CU Copper Peptide Serum for All Skin Types