Glossary
Needle gauge
Also called Gauge, G, 31G, 30G, 29G
A number for needle thickness. Higher gauge means a thinner needle: a 31G needle is finer than a 29G.
In more detail
Needle gauge follows the Birmingham wire gauge, where the number goes up as the diameter goes down. Needles in common medical use run from 7 gauge (the largest) to 34 (the smallest). Insulin syringes are typically 28 to 31 gauge, with lengths from about 6 mm to 12.7 mm (half an inch).
Expert insulin recommendations favor the shortest needles, 4 mm on pens and 6 mm on syringes, as the first choice for nearly everyone. Peptide guides commonly suggest 30 or 31 gauge at 5/16 inch (8 mm) for subcutaneous shots.
Why it matters
Thinner and shorter needles hurt less and still reach the fat layer. Very thin needles take a little longer to push thicker solutions through.
Related terms
- U-100 insulin syringeThe small insulin syringe most people use for peptides. Its scale is marked in units, where 100 units equals 1 mL, so 1 unit is 0.01 mL of liquid.
- Subcutaneous injectionA shot into the fat layer just under the skin. It is the route most injectable peptides use, usually with a short, fine insulin needle.
- Dead spaceThe liquid left in the needle and hub after the plunger is fully pushed. It is not delivered, and it varies by syringe design.
Sources
Each source is labeled by where the information comes from. How we label sources
- Reference workHypodermic needle (gauge)(opens in a new tab)
Wikipedia · checked
- Reference workFrid AH et al. 2016, New insulin delivery recommendations (FITTER), Mayo Clin Proc(opens in a new tab)
PubMed · checked
- Competitor guideInsulin syringes for peptides (U-100 units)(opens in a new tab)
peptiq.io · checked
Updated