Insulin Before or After Meal

I was wondering if you take your insulin before or after your meals? Since i started college a couple years ago i’ve been taking the insulin after i eat because i don’t always know my whole meal before i eat it. Think it makes a big difference in your a1c?

And do you know what your sugr should be 1 after hour eating? Normally I’ll check after an hour and it’ll be about 250 but then by 3 hours after it’s back down to 90 or so

I always take my insulin before my meal & I try to pre-bolus by 10-20 minutes. The only time I don’t is if I am really low. I am sure it makes a difference in my A1c because I am not having the spikes by doing that. I usually try to be back to my starting point an hour after a meal, but I also use Apidra & it gets out of my system faster than Humalog or Novolog.

I’ve always been instructed that whenever possible we should take the insulin 10-15 minutes before our actual meal. It helps prepare our system for the intake of carbs we’re about to make. If you wait until after your done eating to give insulin you’re basically letting your sugars go up, and then you’re bringing them back down.

Insulin, while fast, isn’t instant and needs some time to kick in. For that reason alone it will definately impact your A1c reading because your average glucose won’t be as steady.

SPikes like this are actually worse than higher BG itself. A1c is really just an average, and does not reflect very accurately on your diabetes treatment success. You can prevent them with bolusing earlier. Action of iňsulin then coincides with action of the carbs, evening each other out. That’s the whole point of bolus insulin. For me, 20 minutes usually work best.

I bolus right as I am eating or after. I don’t plan my food enough and hate having to eat at many carbs as I bolus for. I usually don’t go over 160 but if you go that high, then maybe bolus a bit before would help. You could also look at what you’re eating. If you don’t have enough fat/protein in your meal you will shot up really quickly. Just a thought. Good luck!

well, getting 250’s is not a good thing, in fact, it’s pretty bad…
one alternative, if you really don’t know how many Tot Carbs your going to be eating

1-Give yourself a Meal plan of total carbs to stick to and take a Bolus for that 10-15min ahead of time
2-Compromise? take 1/2 ahead of time and the other 1/2 or moreis needed perthe Tot. Carbs After eating.

and you have to try as best you can to avoid going above 150 at 1 hr and get into the 120 range at 2 hrs and 90’s at hr #3

another problem we have to do? We can’t just take a Snack and then Bolus for it… we have to try to always take a bolus-10-15 min ahead of time and then snack afterwards…

I know it’s a real PIA and I’m just as guilty not doing it all the time too.

It’s just another PIA things to put on the list …

Another PIA? Behing High B4 wanting to eat… So I start testing 1 hour ahead of time…to see how things are doing… 1/2 the time I’m too high and take a CB and it helps down the road to get things under better control 1-2 hrs after eating…

hope that helps

The goal of timing insuin to meals is have insulin coincide with digestion. Rapid acting takes 10-20 minutes to start working & it peaks at about 2 hours. You should be taking insulin before meals with 250 one hour after eating. Timing is really important to avoid spikes.

i’m super insulin sensitive. Whenever my sugar is below 150 after an hour it’s definately low by 2 hours.

I meant my sugars 250 an hour after i eat. If i’m high before the meal i’ll take my correction units. Then eat then cover.

I’ve experienced the same issue occurring if I eat foods with a high glycemic index. I find post meal dosing is better for me becasue I have a better idea of how many carbs I will be consuming. I typically do not do anything in terms of correction because I’m usually below 120-140 mg/dl 2 hours later. Hope this helps!

I have struggled with this issue as well. I felt that if I took my insulin before my meal I felt that I was forcing myself to eat everything I took into account when calculating my dose. After trying multiple different ways of handling this, I found the best thing to do was to take 1/4 or 1/2 the dose 15 min. before, or as you start eating, and then the rest after, so that you can adjust it according to what you do or do not eat. Hope this helps.

I’m going to try this today!

Testing 1 hour after eating may not be advisable, especially if you are not bolusing prior to eating - there’s just not enough time for you to digest AND get the insulin working in that time span.

FWIW, I rarely test 1 hour after, unless I have been more or less active than normal and/or I eat a meal that is not “normal” for me.

Fair Winds,

What do you mean by low. If you are at 62 2 hours post, then you might just have a 4-8 carb snack to take you back up at that time. That would be much less stressful on your system than those spikes to 250.

You might also think about adding more fat and fiber to your diet so that the initial kick is slower.


Yeah, but that’s exactly the problem. Your way of bolusing is the exact cause of these spikes. The point is to match action of sugar to action of insulin, which your method doesn’t achieve.

I do not have much feedback for this question as I just started bolusing last week. However I have read that if your meal is low carb but high in fat and protein OR low in GI then you should bolus after eating or half before and half after (which I dunno how you would do this with an insulin pen??). If you are eating something moderate in GI you can bolus when you start and high GI bolus 15 minutes ahead of time. I personally have been trying to figure this out and see if waiting makes a difference. I would like to know if you should bolus before a meal when it is something like a salad?

The Joslin recommendation is no more than 30 points higher 3 hours after bolus. It would be nice to be able to be back to normal at 2 hours but given that the duration of Humalog is 4 hours it isn’t something that one can count on.


You will have to experiment to see what works for you. I have a tendency to go low during the first couple hours after a meal as I eat high fiber/high fat/low GI. As a result, I will calculate my dose and “reserve” .5 -1.4 units to take about 2 hours in so that the insulin matches the carbs. You can do that with a pen - although it does mean increasing the number of injections each day.

I would start by injecting just before the meal and playing with the time after you begin to see patterns.


I have now tried bolusing after eating by mistake (forgot to bolus), giving myself a rather unnecessary spike of 280 (I can see it on the CGMS i have for trial). Bolusing before eating avoids this. It’s as simple as that.