Basal/bolus ratio for type 2 on MDI or pump

I am type 2 with Dexcom G6 and a T:Slim pump with C-IQ since January 2022. My bolus to basal ratio runs around 68 to 70% basal to 32 to 30% bolus. Many type 1 DMs have this much closer to 50/50. I am curious about other type 2 DMs’ Basal/bolus ratio.

When I went on MDI 16 months ago, I came up with my own bolus dosing by analyzing the results from my CGM. I stayed with the same basal dosing I was using with Lantus.

With the pump, I wasn’t quite pleased with the results. It wasn’t bad, but not as good when I was in control with a syringe.

About a week ago, I changed unit:carb gram using a formula 500/TDD and insulin sensitivity factor or correction 1,800/TDD. This did not change the Basal/bolus ratio very much, but it has given me much better results.

When dosing for a meal bolus if C-IQ want’s to reduce it because BG is below what it thinks if proper, but is above 90mg/dl, I hit the X and enter the amount of carb grams.

With this current regime I have not experienced any BG below 75mg/dl. I don’t doubt there will be other changes in the future.

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I won’t comment with my own ratio, since it’s not relevant to your question. I just wanted to comment that this notion of a 50/50 split has largely fallen out of favor, except for maybe as a jumping off point for new patients.

It’s something that lingers from the old days of animal/humulin insulins, sliding scales, and carbohydrate exchanges where we literally ate to our insulin doses instead of dosing for the food we eat.

Now there’s better tools available to us. Our basal needs are whatever they are, mostly irrelevant to our bolus dosage. (Excepting however our diet choices affect our insulin sensitivity.) How much bolus insulin we need is entirely based on diet choices. Someone choosing to eat healthier than “average”, by reducing carbs and/or fat, is really going to tip the scales towards the basal side. It would be sheer coincidence if someone is bolusing equal to their basal, or perhaps they were trained to eat that way by a fixated medical professional.

For Type 2, I would think it’s really dependent on how an individual’s diabetes is progressing, and which approach they started started with. Seems like it’s normal to start EITHER basal or meantime insulin first, but seldom both together. In that case, it’s going to be a 100%/0% split.


Also speaking as a T1 the basal calculation is simple, albeit tedious; do not eat (or drink, apart from water) for 24 hours, adjust basal until your BG is neither going up nor down. With C-iQ I guess it’s just a matter of not eating and seeing what it ends up with.

Some people use “basal” as a way of doing a temp bolus, but if you are using C-iQ that it irrelevant since it doesn’t (can’t) support temp boluses in any meaningful way.

The main problem is fat; fat can take a very long time to digest and still ends up requiring insulin if you aren’t eating anything else. You have to get everything out of your system to get a correct basal.

Yeah, but then you are fighting the algorithm (if I understand correctly that you overrode the attempt to raise your BG). It wants (IRC) 150 but it’s a few weeks since I read the manual. This looper post might help:

It’s probably out of date. So far as I could see on the basis of more recent readings there isn’t much choice; if you buy it you have to target something 120+ and if you don’t you will be forever fighting it. I suspect this is why looping may not be the best choice for T2s, but YMMV :slight_smile:

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I admit that I was somewhat hesitant to turn my control over to C-IQ, but I went a head with it. Doing the slight override appears to be working well. It keeps my BG where I want it, Goldilocks style, not too high and not too low. I allow the bolus decrease if BG is <90mg/dl.

Anyway, the reason I posted the question is, I want to make sense out of stuff. I have an analytical mind that was trained to be even more so. I also have a terminal condition, malignant curiosity.

I exasperate my wife, “Why do you care about (fill i the blank)?” “No reason, Sweetie, I just want to know.”


Indeed, FWIW:

(And I do BS about C-iQ since I’m still on Dash and I don’t loop, good BS though.)

I am MDI, diabetic 32+ years 100% bolus Humalog 0% basal. I tried all the Lantus, Levemir, etc and they all caused frequent and regular nighttime hypoglycemia events. I fought my endo tooth and nails to stop basal years ago and never had another nighttime hypo since. Continuous Dexcom clarity reports to back this up, finally convinced her after a couple of years. My A1C/GMI averages in the 5.7% range, My TIR is in the high 90% range and standard deviation about 20. No Basal made me a very happy diabetic.


@John_Bowler , I can’t find the “See My CGM” article in any professional journal list. It lacks juried or peer review and the author lacks credentials.

We are all individuals with different reactions to carbs, proteins, & fats. Insulin does not act instantly either. The combined reaction to, digestion of, & insulin interaction, means everything is in play & needs consideration. Therefore, the collection from FUDiabetes is again without solid standing.

@Luis3 , the question you have posed was best answered straight away by @Robyn_H . We are each individuals and it is unsafe and potentially harmful to place any standing on random unscientific posts here. The discussion should be with your prescriber and your concerns put to rest there.

I am a 20+ year user of various Dexcom models & pumps by Animas & Tandem. I have participated in research with Pods. I have been on a Tandem t:Slim X2 with CIQ like you describe for 28 months. My A1C runs 5.0 - 5.4 with a 4.7 recently.

SUGGESTION: if you are going to go on a chase, focus on three things that you can get from the Dexcom Clarity software. [1] average glucose over time, [2] standard deviation, & TIR (time in range). Here is a screen grab of mine from Sunday morning.

Hopefully, this collection will provide navigational assistance to you on your journey and reinforce the importance of using properly vetted information.

If you wish to search out information from quality sources, one of the best is the US National Library of Medicine found at


Hope this helps.

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Hard to say, since my boluses (?) can vary enormously, but 90/10 is a good guess, Toujeo/Novorapid.

Good luck.

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Luis3 ,

The same strain that killed the cat?


Well, I am a cat dad.

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Eh, no; it’s a product review/comparison.

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In that case, I guess the ‘patient’, who in any case will be the one who gains or suffers from whatever is written there, will have to decide for himself, using his own criteria, how much value to assign to it.

Speaking of peer review, does anyone else here remember the history of Dr. Bernstein’s magic machines?

And speaking of credentials, does anyone remember Thomas Szasz’ discussion of medical licensing?

From Peer Review Revue - ScienceDirect , which was almost certainly peer reviewed:

‘Peer review is a relatively recent standard of science. Nature itself instituted formal peer review only in 1967. It is well known with near-mythical status that Einstein was severely critical of the external review process, frequently quoted that had not authorized the editor-in-chief of Physical Review to show his manuscript “to specialists before it is printed,” and informing him that he would “publish the paper elsewhere.”’

And now for our on-site reporter:

I am not qualified to do anything (Certificate available on request.)

  1. A while ago, I wrote the improvements demanded by one of the peer reviewers in a very respectable journal, and the article was then accepted. If anyone knew the field I’m talking about, they would be terrified.

  2. More recently, I accidentally wrote a protocol for … That should scare you even more.

I could go on and on with my list, and if anyone annoys me, I will.

Basal as a percentage of TDD has several problems and doesn’t make sense to me for anything except a starting point. I have only been able to find two studies, both in hospital setting. Basal’s were 30 and 40% of TDD. Bolus depends on how many carbs are consumed, while basal shouldn’t. More carbs and basal goes down as percent of TDD and vice versa. It may also depend on how much insulin a PWD’s pancreas is producing.

My basal currently runs 15-20% of TDD with average of 110 daily carbs. I have come to the conclusion that 50% basal is a carry over rule of thumb from MDI before test strips and CGM. Basal testing and more enlightened endos have finally put the 50% rule behind me.

End of rant.


I don’t aim for any% I just g with what my pump delivers and since it’s now mostly automated, it’s a good way to see what my basal needs are.
I run nearly exactly half basal and half bolus.
Today I used 24 units basal and 26 bolus. That includes a few corrections.
I eat a high carb and low fat diet and I’m type 1 so I don’t know how that plays into it, but I’ve always used about25 units basal since I was diagnosed 35 years ago

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