The Ordinary Multi Peptide Serum for Hair Density Space NK Copper Peptide Serum Anti Aging Face Oil for Glowing Skin We're often asked what the difference is between our two Buffet serums. Do they target different concerns? Is one for more mature skin? Is one better suited to dry skin? As we're GHK Cu (Copper Peptide) is a naturally occurring peptide in the body that binds with copper to support cell repair and renewal. As we age, our levels decrease and thats where supplementation or