Are Peptide Injections Safe? What Every Aesthetic Provider Should Know Beginner's Guide to Peptide Therapy [2026] Hard Lump Under Injection Site: Treatment, Causes, and More MyEczemaTeam 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 6 month GHK CU check in Main takeaway: skin transformation takes time. GHK CU peptide binds to copper and activates genes involved in wound healing, collagen synthesis, and skin remodeling. On the face, this translates