U-100 insulin syringes
A fixed needle and a unit scale, which is what makes a small dose readable. The finer gauges are noticeably more comfortable and slightly slower to draw.
What a U-100 insulin syringe is
U-100 means the barrel is graduated for insulin at a concentration of 100 units per millilitre. One hundred units fills one millilitre, so a unit mark is one hundredth of a millilitre. That is the whole reason these exist: at that scale a millilitre scale is unreadable, and a unit scale is not.
The needle is fixed rather than screwed on, which removes the dead space where a luer fitting would be. On a small dose that dead space is a meaningful share of what you drew up, which is why a fixed needle syringe is the standard choice for anything measured in units rather than millilitres.
These are single use and sterilised with ethylene oxide. They are consumables. Whatever goes in them comes from your pharmacy on a prescription, and we have nothing to do with that part.
Which gauge and length to choose
Gauge is thickness and the scale runs backwards, so 31G is finer than 29G. A finer needle is noticeably more comfortable and draws more slowly, because you are pulling the same volume through a smaller hole. A thicker one fills faster and is easier to feel going in.
Length decides what layer you land in. For an injection into the fat under the skin, the shortest needle available is the one to reach for, and Australian and international diabetes guidance has moved that way for exactly this reason: a short needle is very unlikely to reach muscle whatever your body size.
If you are not certain which pair you want, the Gauge Finder asks three plain questions and tells you, without asking what you are injecting.
Everything on the box, before you buy.
The incumbents make you register to see a price. The batch and the expiry you are shipped are the ones printed here.
Questions about U-100 insulin syringes
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