Subcutaneous Injection Sites and Instructions for Safe Self Administration Subcutaneous Injection Sites and Instructions for Safe Self Administration GHK Cu vs NAD+: Which Longevity Peptide Should You Take or Stack? BodyPharm GHK Cu My Antidote 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