What size needle do you use for peptide injections?

This site does not sell products and does not recommend a specific needle. Measured in the insulin injection literature, a needle of 4 to 5 millimeters inserted at a 90 degree angle stays subcutaneous in virtually all adults, while needles of 8 millimeters or longer carry a meaningfully higher chance of reaching muscle, especially at the thigh and in thinner people. Standard insulin syringes are sold in roughly that 4 to 12.7 millimeter range for that reason.

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.