Neck Tightening with GHK Cu & SNAP 8 Hydra Needle Peptide Treatment Subcutaneous Injection Sites and Instructions for Safe Self Administration Bounce Back Better with Peptides for Injury Recovery Still injecting in the same spot every time? Read this. Where you inject your peptides can actually affect absorption, comfort, and results. Quick guide: Abdomen: fastest absorption Upper arms GHK Cu Peptide Therapy: The Definitive Clinical Guide to Gene Modulation, Protocols, and Efficacy