Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives 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 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 CJC 1295 Ipamorelin Benefits, Side Effects, and Cost: The Complete Patient Guide Perfect B Peptide Therapy Explained Relive Health