Needle Gauge
A measurement of needle diameter — higher gauge numbers indicate thinner needles. Peptide self-injection typically uses 29-32 gauge needles, which are very fine and minimise pain. Modern auto-injector pens use ultra-thin needles (30-32 gauge) to improve patient comfort and adherence.
Technical Context
The Birmingham Wire Gauge system: higher numbers = thinner needles. Common gauges for peptide injection: 18G (1.27mm OD, used for reconstitution/drawing up), 21-23G (0.82-0.64mm, IM injection), 25-27G (0.51-0.41mm, SC injection with syringes), 29-32G (0.34-0.24mm, SC injection with pen devices). Ultra-thin needles (31-32G) in modern pen injectors significantly reduce injection pain — many patients report minimal or no pain with these devices. Needle length also matters: 4-5mm needles for SC injection in most patients (eliminates need to pinch skin), 6-8mm for patients with thicker SC tissue, 25-38mm for IM injection depending on body habitus and site.