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 Brava Longevity GHK Cu is a naturally occurring copper peptide that has been shown to have numerous beneficial properties, particularly in skin care and tissue regeneration. tI has gained popularity due to its GHK Cu Peptide 100mg Australia Collagen & Skin Repair Peptide IM AEGYO