Insulin syringes were the only commonly used way of delivering insulin for much of the 20th century. Towards the end of the 1990s, insulin pens became more commonly used. Whilst less popular these days, syringes are still in use by people with diabetes.

Insulin needs to be injected subcutaneously, that is into a layer of fat between muscle and the skin.

Insulin syringes are available in a number of needles lengths:

• A short length of needle would be less than 10mm
• A longer length of needle would be over 10mm long

The gauge (width) of insulin syringes tends to be slim because of the regularity at which injections of insulin are taken.