Correction Bolus

I am new to MDI of insulin. My doctor gave me the brief explanation of when to inject before meals and what insulin/carb ratio to shoot for. My question, at what blood glucose level do you normally correct after a meal? Do you wait for the 170 level or higher? Is 160 mg/dL a decent level? Do you wait two hours after the meal to make any corrections? Thanks in advance for any experience you can share.

Hey Chris,
I am sorry you are heading down the insulin to survive group but once you get the hang of it, you will probably start feeling better.
That said, your question is definitely a doctor or CDE question. No idea what you current insulin doses are, your carb ratios and do you have different ratios for different meals(many of us do), correction numbers are different for what part of the day for many of us, and what your target range is. Once you have this talk with your medical team, it is up to you to start your daily life experiments. Each day will issue a different set of numbers and reactions to those numbers. And what works today might not work tomorrow.
Sorry I don’t have an answer for you but I do recommend a book by John Walsh Using Insulin. It is a resource book I still have in my diabetes library.
Good luck and once you get some targets and numbers from your team, there are many who can help with fine tuning. It’s just most of us don’t like giving dosing plans. I am not a medical professional except for my own diabetes.

Unfortunately, everyone’s insulin needs vary. Your doctor can only start you in a certain direction. Your best bet is going to be too gather lots of data in these early early days. I would highly recommend going into your app store of choice and typing the word “insulin” into the search field. There are LOTS of app options to choose from.

At the bare minimum you need to be recording in it what you eat, his much insulin you took and when, and all your fingersticks. The more data, the better!

You can’t know when you need to correct, though, without knowing how much insulin you have on board, though. So look for an app that mentions the words timer, insulin on board, or IOB.

The fast-acting insulin you inject takes 15-30 minutes to start working, but can contribute to lower your blood sugar for nearly 5 hours after a bolus. You’ll only really notice it working for probably 2.5-3.5 hours, though. That’s what the app you choose will use to tell you his much insulin you still have working to lower your BG. Even if you’re above range, you don’t want to bolus if you have enough active insulin still working… Otherwise you could face serious hypos later.

The only logging app I have personal experience with is MySugr, which I found amazing for helping me learn about my own insulin specifs… But it may not be for everyone. You literally feel your pet Diabetes monster data, and it made the data entry drudgery more fun. And had great analytics to boot. But there are lots of other options out there if that’s not your thing.

Thanks for your responses! I’ve definitely been collecting data on BG levels for a few months now. I will look into MySugr and start collecting data on how many units I use per meal type. I am trying to figure out the best BG range to try and shoot for with insulin therapy, regardless of how much insulin I need to take to get there. Is anything under 180 and above 70 great, or should I try to keep it between 70 and 120? This will come with experience I know, just curious what others shoot for.

It varies a lot. I think your best bet is to make incremental goals—if currently you are way outside of 70-180, that’s probably a good goal. If you can do that ok, then try for a tighter one. If you can get a goal of 70-120 to work for you, fantastic. So people are able to target even tighter than that. I know I can’t—I have way too many factors going on that increase variability in my blood sugars to make that realistic for me. Also my goals fluctuate over time based on what’s going on (there are times for example when I make my acceptable range higher overnight because I desperately need sleep and am prioritizing not risking getting interrupted (either by lows or by high alerts on my Dexcom) over tighter control.

Personally, usually I set my Dexcom to alert me at 140—sometimes I raise that to up to 180 for various reasons (but that’s usually going to lead to blood sugars going into the 200s if I wait until that point to respond).


This could be a good goal if 180 is peak right after meal, but then ideally returns to 80-120 between meals and overnight.

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Hi Chris, When I first started on MDI my goals were pretty basic because it took a while to get a handle on bolus timing, doses and corrections for different foods. Example a protein rich breakfast was a totally different experience than a protein rich dinner. And restaurant food was a total guess.

Anyway, the first goal I set was minimizing the number of times my BG spiked over 200. I did some polling of seasoned Type 1’s and convinced myself that fewer than 3 weekly excursions above 200 would be decent. Using a nice round (and conservatively high) number like that got me started on proactive corrections after meals and helped me tighten the goal as time went on. It was sort of a progression from uneducated guesswork towards educated guesswork. The Walsh book and time spent with my endo looking at CGM plots were very helpful during that initial trial and error.

Years later I have continually tightened my goals, especially after I started with a pump. But tightening those goals required the basic knowledge of my ratios, how and when different meals cause a risk of spiking BG, and on down the list. And all of this things vary between individuals and will also vary for each of us depending on many factors. Hang in there, a lot of the correction bolus guesswork will become automatic after you’ve done it 24/7 for a while.


I consider anything under 200 a success.
But, you will prob begin to tell what is typical for you, and so you will see if something is off before you hit the 2 hour point.

Generally, though, you measure before you eat, and 2 hours after to see if the dose was correct - should be a similar number.

Correction insulin is different. That wont fully kick in for 4 hours. So, you test before administering it and 4 hours after.