Even when you can't dilute insulin, it's possible, with a lot of patience and a good magnifier, to dose insulin in fine gradations. Since a small dog or cat may weigh 1/10 what an average human does, it shouldn't be surprising that a 1 unit change in a human is sometimes like a 1/10 unit change in a small animal.

With U40 insulinEdit

With U40 insulin, you can dose insulin to a precision of 0.2 units by using a U100, half-unit marked syringe, and converting.

With U100 insulinEdit

But with U100 insulin, all you can do is use patience and good eyesight to "eyeball" fine doses. Consistency is more important than accuracy -- if you can give the same amount reliably tomorrow, you have succeeded.

It is indispensable to use half-unit marked U100 syringes. The insulin syringes with half-unit markings are available here:[1][2]

Pictures methodEdit

The Fine Doses Picture guide shows one numbering method.

Note that some syringe makers have inconsistent zero line adjustments with significant variation. See this discussion:,1462377

Fat/thin/touching methodEdit

Another works like this:

  • 0.5U = on the 0.5U line
  • 0.4U = thin 0.5U - touching the edge of the line
  • 0.3U = thin 0.5U - no longer touching the edge - some daylight between
  • 0.2U = fat 0.0U - not touching the zero line
  • 0.1U = fat 0.0U - touching the edge of the line
  • 0.0U = On the zero line

Droplet methodEdit

Stefanie & Toonces of the FDMB use a "droplet" method.[3][4]


  1. Diabetic Promotions Link to BD Half-unit U100 Syringes, 5/16" needle, 31G
  2. Diabetic Promotions Link to Monoject Half-unit U100 Syringes, 1/2" needle, 29G
  3. Descriptions of Stefanie's droplet method
  4. more on Stefanie's droplet method
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