Redness after a peptide injection can feel alarming but in most cases, its completely normal. , If youve noticed a pink or red halo at the injection site especially with peptides like GHK Cu 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 Injectable Team Wellcore Subcutaneous (SC) and Intramuscular (IM) Injections Must Knows for Subcutaneous administration: Pinch skin with non dominant hand and hold syringe with dominant hand Always inject: 2 inches away from umbilicus (for abdomen) 3 inches