How much is one unit of insulin?

I use pens, either prefilled or with a cartridge. Mine contain 3ml, with 100 units per ml. I can take as little as half a unit with these, the pen has a piston inside, and a dial on the end - you just dial up how many units you want after doing an air shot, stick the needle in and press the button. These are the standard way of injecting insulin in the U.K. now, are you in a different country?

Do your syringes measure ml or units?

I’ve always used pens, they came out not long before I was diagnosed 20 years ago, so apart from the odd occasion in hospital I’ve never used a syringe on myself. My pens seem to give a full 300 units, so the tiny bit that’s left is extra, to make sure you get what it says on the cartridge or prefilled pen.

Does that tiny bit really matter, I mean, is the risk of pulling up an air bubble into your syringe worth 10-15units? I’m assuming you pay a lot for it where you are, making this worthwhile?

1cc is a cubic centimetre, which is the same as 1ml. So one of your syringes, if you have drawn up a full 1cc/1ml would contain 100 units, assuming you use a standard strength insulin. Some are available at double, triple and even 5x strength for folk who have to inject a lot. Might that be an option for you, to save having to inject such large volumes?

And yes, half a unit drops my sugars by approximately 1.5mmol if it’s slightly at the top of my desired range. The higher it is, the more it needs, as well as earlier in the day. But in the afternoon and evening, if I find myself running at the mid to high 7s, I’ll inject half a unit and that will bring me down to 6 or so. A full unit would leave me more likely to hypo.

Hi, i'll be interjecting a bit as i am suddenly confronted with this problem too.
I have been using Apidra Solostar (pen, 100units/mL, 3mL) for several years by drawing with a diabetic syringe (1mL/cc). I am told by my doctor to take 2-3 "units" per meal time. So what i do is draw that amount measuring by the lines on the syringe.
I don't like the pen needle because i thought the needle was too short, and either the units aren't accurate OR my starting dose - if the units on the pen differ from the syringe - is too small. I also noticed that when i was using the pen needle, it tends to waste a few drops after injections, and bubbles enter the pen.

Just this week my doctor introduced Toujeo to me, and told me that it is more concentrated vs the contents of the Lantus vial. I had asked about the amt of units to use - same units as Lantus - and how do i convert the dosage from pen units to syringe units - to which she was horrified and told me not to use syringes. I assume she was worried about miscalculated dosages.

So now i am wondering if i had been using a much larger amt of units of Apidra than is recommended and i had no idea i was doing so. Does someone know the conversions for pen units to syringe units?

slaxx said:

Hi, i'll be interjecting a bit as i am suddenly confronted with this problem too.
I have been using Apidra Solostar (pen, 100units/mL, 3mL) for several years by drawing with a diabetic syringe (1mL/cc). I am told by my doctor to take 2-3 "units" per meal time. So what i do is draw that amount measuring by the lines on the syringe.
I don't like the pen needle because i thought the needle was too short, and either the units aren't accurate OR my starting dose - if the units on the pen differ from the syringe - is too small. I also noticed that when i was using the pen needle, it tends to waste a few drops after injections, and bubbles enter the pen.

Just this week my doctor introduced Toujeo to me, and told me that it is more concentrated vs the contents of the Lantus vial. I had asked about the amt of units to use - same units as Lantus - and how do i convert the dosage from pen units to syringe units - to which she was horrified and told me not to use syringes. I assume she was worried about miscalculated dosages.

So now i am wondering if i had been using a much larger amt of units of Apidra than is recommended and i had no idea i was doing so. Does someone know the conversions for pen units to syringe units?

Click to expand...

It is important to get this right and I think you should ask your pharmacist who will be able to advise you (or go back to your GP).

Units of insulin are standard throughout the world (they used to be called International Units) so there is no such thing as a 'pen unit' or a 'syringe unit'. You might have a syringe which is calibrated in Units of insulin but it should only be used for the strength of insulin indicated (for example, it may say '100 Units 1ml' which means it should only be used for insulin that contains 100 Units per ml).

Apidra Solostar contains 100 Units of insulin per ml of solution, so to give 2 Units, you would have to inject 2/100mls i.e. 0.02mls. This is a very small volume which can be measured accurately by an insulin pen (if used correctly) but is too small to be measured accurately with a 1 ml syringe.

Toujeo contains 300 Units of insulin per ml of solution (look in the patient leaflet to check this correct ) so it is 3 times as concentrated as Apidra. To give a dose of 2 Units of insulin you would have to inject 2/300mls i.e. 0.0067mls. Again, this can be measured accurately by a correctly used pen but NOT by a 1 ml syringe. The medicines advice for Toujeo says
For your own safety, Toujeo should be used as recommended i.e. using the insulin pen, not a syringe.

Tagging @catapillar for advice.

Thank you for your response @Dark Horse, and will also be waiting for possible further advise from @catapillar.
My insulin syringe has a U-100 marking. I think this is what you were mentioning about IU insulin concentration? It is same with the Apidra Solostar. (I'm still hoping it is correct because, holy cr*p, punch in the face lol ><)
I will definitely not use an insulin syringe for the Toujeo. Quite aware of the dangerous consequences. Thanks.

Ive got no idea, sorry. I've never used a syringe. I haven't got a clue what you're talking about.

Oh, i think i should be in safe ground. Reviewed every marking on the syringe. It says For U-100 Insulin, 1mL/cc, and the measurement gauge is specifically written up to 100 Units, at increments of 2 Units. It should work with any U-100 insulin as it measures by Unit, not by mL.
Sorry about the confusion. I only learned of the differences/importance of these things now, and only just noticed everything. I wish doctors mention this to their patients at least as precaution. Toujeo with syringe is definitely out of the question.

Gork said:

I have been using syringe injections for over 20 years now and recently tried the Novolog FlexPen. I found the needles to be too short and believe that one tip broke off in my leg. I went to longer needles but could not make the adjustment and went back to syringes.

I did not like the fact that each pen throws away 10 - 15 measures of insulin after it no longer dispenses. For a while there, I was using a syringe to salvage that last insulin and filled a vial in a short time .The box claims that each pen contains 3ml bit does that include that which is being discarded?

The syringe does not indicate much but, now that I look at the box, it shows that they are: 1cc, U-100, "For 100 units or less". Although that may answer my question, it does not seem to reflect what I am reading after a significant internet search. My doctors and pharmacists did not seem to be able to answer the conflict either.

Does injecting just 1/2 of a "unit" actually have any effect?
.

Click to expand...

Truly, there is no conflict. Merely I think a lack of understanding of insulin "effect units" versus insulin "volume units".
As you are yourself a Type2, with a very high demand for daily insulin intake, then it may be challenges to understand that some of us Type1 like myself only need like 3 units of fast acting insulin to metabolize a whole evening meal. So for me, 1/2 unit more or less can make the big difference between getting too little or too much insulin to keep my bg stable.

To me its a difference of 16%, while for you the difference is minor as its around 0.5%.
For you being such a high-volume insulin user, then the pens makes much less sense than to most Types1. E.g. for me a pen typically lasts 10-14 days! So the convenience by using them is superb compared to the more steps and care you need using the old "syringe+needle+alcohol swab+insulin vial" model (did that for 10+ years at first).

Regarding your 'concern for waste' then I will have to argue a bith with you there. As actually the pens have much less wastage of insulin if that is your true concern (though it shouldn't be). So you are right, the contents of the pen is 3ml in total. Meaning the last 0.08-0.10ml that you cannot inject out is being wasted in a pen. However, it is actually the same and in most cases even a higher volume you throw out when using the old syringe/needle model. It is maybe just not so appearnt to you, but indeed the insulin is sitting in the bottom of the syringe just at the plunger and into the space you have there at the needle connector and into the beginning of the needle connector also. And this you throw out every single time you need to take an injection. While that is not the case with the pen. (as we simply leave the same needle in, through to the end of life of the disposable insulin pen)

As with anything with human beings involved - We are all different!
Find the way that works best for you and enjoy life in any aspect you can!

Dark Horse said:

It is important to get this right and I think you should ask your pharmacist who will be able to advise you (or go back to your GP).

Units of insulin are standard throughout the world (they used to be called International Units) so there is no such thing as a 'pen unit' or a 'syringe unit'. You might have a syringe which is calibrated in Units of insulin but it should only be used for the strength of insulin indicated (for example, it may say '100 Units 1ml' which means it should only be used for insulin that contains 100 Units per ml).

Apidra Solostar contains 100 Units of insulin per ml of solution, so to give 2 Units, you would have to inject 2/100mls i.e. 0.02mls. This is a very small volume which can be measured accurately by an insulin pen (if used correctly) but is too small to be measured accurately with a 1 ml syringe.

Toujeo contains 300 Units of insulin per ml of solution (look in the patient leaflet to check this correct ) so it is 3 times as concentrated as Apidra. To give a dose of 2 Units of insulin you would have to inject 2/300mls i.e. 0.0067mls. Again, this can be measured accurately by a correctly used pen but NOT by a 1 ml syringe. The medicines advice for Toujeo says

• A syringe must never be used to withdraw Toujeo from the cartridge of the SoloStar pre-filled pen or severe overdose can result

For your own safety, Toujeo should be used as recommended i.e. using the insulin pen, not a syringe.

Tagging @catapillar for advice.

Click to expand...

Agreed - Watch out when switching from Lantus to Toujeo if using syringe/needle and not the pre-filled SoloStar pen!
Per volume it is 3x as effectful as the Lantus. Which I of course can see will be a convenience especially for the Type2s who take a very high volume per day of basal (certainly compared to some of us insulin sensitive Type1s)
And for us it would not be possible to be sufficiently precise with the dosing if using a syringe/needle model.

For some of you here on this forum, you might also remember some 30 years or so back, when this International Unit measure was introduced to the market, as most types of insulin were then re-launched in more concentrated versions (as the purification process technologies now enabled that), so we typically only needed 2-5 times less volume of insulin to get the same effect as we previously had sucked out from the vials in the 'old days'.

And hereby some trivial diabetes history fun facts:
One International Unit of insulin is defined as the amount of insulin that will lower the blood glucose of a healthy 2 kg rabbit that has fasted for 24 hours to 2.5 mmol/l (45 mg/dl) within 5 hours!

And when comparing that into human beings 1 IU of insulin is equivalent to 0.0347mg of human insulin.

Yep, I am quite happy we agreed to use the IU as standard measure.

Celsus said:

Agreed - Watch out when switching from Lantus to Toujeo if using syringe/needle and not the pre-filled SoloStar pen!
Per volume it is 3x as effectful as the Lantus. Which I of course can see will be a convenience especially for the Type2s who take a very high volume per day of basal (certainly compared to some of us insulin sensitive Type1s)
And for us it would not be possible to be sufficiently precise with the dosing if using a syringe/needle model.

For some of you here on this forum, you might also remember some 30 years or so back, when this International Unit measure was introduced to the market, as most types of insulin were then re-launched in more concentrated versions (as the purification process technologies now enabled that), so we typically only needed 2-5 times less volume of insulin to get the same effect as we previously had sucked out from the vials in the 'old days'.

And hereby some trivial diabetes history fun facts:
One International Unit of insulin is defined as the amount of insulin that will lower the blood glucose of a healthy 2 kg rabbit that has fasted for 24 hours to 2.5 mmol/l (45 mg/dl) within 5 hours!

And when comparing that into human beings 1 IU of insulin is equivalent to 0.0347mg of human insulin.

Yep, I am quite happy we agreed to use the IU as standard measure.

Click to expand...

i was quite confused about the switch myself, thus i needed answers. i got puzzled because the doctor's introduction to Toujeo was that it was 3x more concentrated than Lantus, but that i needed to inject the same amount of units as Lantus! so i was thinking "is it gonna be a sudden total of 39 units in my body then??" the rest is history.

hah! that last part. it's good i only knew of it simply as IU. to think someone had to compute all of that before the application of the current standard measurement lol

It's perfectly possible to use a concentrated insulin with a u100 calibrated syringe, I've done so for a couple of years. You do need to be very clear in your own mind about what you are doing, and understand why the markings on the syringe are not a direct measurement of the insulin.

About the pens, I was told not to leave the pen needle on the pen between injections because insulin can leak out. I was also told to use a fresh needle for every injection, but stopped that fairly quickly as the mound of spiky little things grew. Has this changed?

Also, poor repeatedly hypo-ing rabbits!