Why does an injection sting or burn?

Several factors are documented contributors to injection site pain in the parenteral formulation literature: the pH of the solution, its temperature, injection speed, and preservatives such as the benzyl alcohol added to bacteriostatic water, which sits at roughly pH 5.7. Injecting through alcohol that has not dried is a separately documented cause of extra stinging. None of this has been tested specifically on the compounds this site tracks, only on injected biologics generally, so treat it as the best available explanation rather than a proven finding for any one peptide. Full detail at /injecting.

Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use.

Part of injecting: sites, needles and safety. Subcutaneous vs intramuscular, where people inject, rotation and lipohypertrophy, needle gauge, aseptic technique, why it stings, and sharps disposal. Full walkthrough at /injecting.