THE MOST COMMON REACTION of Sermorelin peptide therapy is related to local irritation around the injection site, which occurs in around one of every six patients. Though this side effect is relatively common, only a small minority of patients find the irritation bothersome enough to suspend therapy. There are other side effects which occur very infrequent, in less than one percent of patients. These side effects include: severe drowsiness, hives, vomiting, headache, nausea, difficulty swallowing, chest tightness and pallor, distortion in perception of taste, and flushing of the skin.  Obviously, stop the therapy if these occur and contact your physician.