Afrezza Units & Insulin:Carb Ratios

This video explains why insulin:carb ratios don’t work with Afrezza, no matter how hard you try.

Afrezza works so differently to previous diabetes treatments, and yet there is nothing in the box explaining how or why. It works so differently that for a while I wondered if I had a bad batch.

This video explains why the labelling on the box is unhelpful and confusing. The units just can’t be compared, and it takes a while to work out that Afrezza has two independent effects.

The first phase begins immediately but it doesn’t lower blood glucose, instead it temporarily stops it rising. This effect seems to be responsible for all the weird and wonderful properties of Afrezza, the first phase does not happen with previous insulins.

The second phase, however, works like a small dose of injectable insulin. It lowers blood glucose, and takes longer to start working. This is the only phase of Humalog or Apidra.

Previous treatments work by flooding the body with an unnaturally high level of insulin for hours, in order to slowly lower high blood glucose levels. Afrezza stops blood glucose rising in the first place using the natural first phase signal to the liver instead. This means that for the first time much lower, more natural levels of insulin can now be used in Type 1 diabetics.

– Matt



  1. Great video and explanation – thanks for sharing.


  2. The package insert does give instructions: 1-4 u of regular injected insulin corresponds to 4 unit cartridge, nothing confusing here.


    1. The confusing thing is that 4u of Afrezza works completely differently to 1-4u of injected insulin. 4u of Afrezza lowers blood glucose by approximately the same amount as 1-1.5u of injected insulin, which is very confusing until you get the hang of its two separate actions that I try to explain in the video. If you wanted to lower glucose that was high by an amount you would previously use 4u for, you might find that even an 8u cartridge of Afrezza wouldn’t get you there. That seems confusing without an explanation in the box.


  3. As a correction bolus, I find that 4-unit Afrezza will lower my BG equal to about 2 – 2.5 units of humalog. When eating, I find that it equals almost 2 units of humalog. I also think that any physical movement will cause it to be much stronger. For example, if I take it and go to sleep , it doesn’t work nearly as well as if I take it and go shopping. That is true with any insulin but it is much more so with Afrezza.


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