Peptide injections can sometimes cause redness or itching at the injection site, but most of the time this is not a true allergy. In the skin, we have mast cells that contain What causes a localized histamine reaction after a CJC (Growth Hormone Releasing Hormone) ipamorelin injection? Peptide Shots in St. Louis, MO The Saint Louis Med Spa That peptide reaction youre panicking about? , Red welts. Itching. Flushing., In most cases, this isnt an allergic reaction its mast cell activation., Your body was already inflamed, stressed, or Q: Why can peptides sometimes cause flushing, itching, or redness?, A: Because some peptides can turn that alarm up too fast., This can happen when:, The dose is high, The body absorbs it quickly, CJC 1295 Peptide Clinics