The size of the needle used in intramuscular injections depends on the specific muscle receiving the injection. For example: If the patient is an adult and if the injection site is a gluteal muscle like the gluteus maximus, the size could be a 20 or 22 gauge needle. If the patient is an adult and the injection site is the deltoid muscle the size/gauge of the needle could be a 23 or 25 gauge. The larger the number means the smaller the needle. A very large needle is a 14 gauge, as the numbers go up, the size goes down. Needle size with children depends on age of the child and also which muscle will receive the injection. Needle sizes/gauges are: 14, 16, 18, 20, 21, 22, 23, 25, and 27.
The larger the number the smaller the needle.
22 -25 gauge needle,
I advise you to ask your doctor.