GHK Cu Peptide Regenerative & Cosmetic Research Injectable GHK Cu: Beginner's Guide to Copper Peptide Before you decide to begin using the copper peptide, GHK Cu, be aware it stings and leaves behind big, red welts that then leave a lovely bruise. , In order to reap the glow benefits, you need to CLEARED Copper Peptide Skin Care Cream For those of you that take ghk cu, why is this so bad? It's never been this bruised. But is always swollen, red, and burns like hell. I can only tolerate every other GHK Cu update! Stinging has subsided, still leaving a little bit of a welt but much better than before! #peppers #ghkcu #copper