For subcutaneous injections, using shorter needles (4 5mm) is the safest choice to ensure medication stays in the fatty layer and avoids muscle injury. A 4mm needle is ideal, minimizing pain while keeping GHK Cu Copper Peptide: Dosage, Before and After Results, and How It Works Perfect B GHK Cu Copper Peptide: Dosage, Before and After Results, and How It Works Perfect B Skin Micro Infusion Peptide System GHK Cu 0.05% GENVEX How much GHK Cu should I inject daily? GHK Cu 50MG Oneday Compounds