Such a thing as too much MDI?

Hi everyone,

Been a diabetic for 15 years. I’ve had the pump for some time but came off of it because of scarring and general discomfort with it. I’m also fairly lean and don’t have much real estate for pump sites.

As a result, I’ve been using MDI for quite some time. I’m fairly flexible with how many times I inject during the day, sometimes going up to as much as 8 - 10 injections a day.
Now my worry is about the effects of taking so many injections a day. I knew that with the pump I had scars that last up until today, but should I be worried about any adverse effects of taking too many injections?

I use a 4mm needle in the back of the arm, buttocks, and abdomen. Using FIASP and Tresbia.


When docs look at my belly, rear end, or legs, they say they see scar tissue. Or my fingertips. But to me, well, that’s just me.

Arguably, decades ago when animal insulins were common, I think site rotation was more important because everyone was aware of the problems of scarring and the way animal-source insulin affected fat distribution in the area. Look up “lipohypertrophy”. So it’s not just all the little punctures, there’s actual stuff happening to the tissues under the skin too.

I think site rotation is still important today but I don’t think the medical practitioners think about it as much or push it as much. Admittedly medical visits are a lot different today than 40 years ago. 40 years ago there was a lot more touchy feely pokey stuff in a doctors visit and today it’s almost all about lab tests.

I myself am not perfect at site rotation. I have my favorite sites and without a doubt I use them in preference over other sites that are in all the textbooks but I do not like using.

Below is a link to a review article on the subject. Wow, I look at all the bad practices (including needle re-use) that make things worse and I’ve done all the bad things so many times!!!

Great questions as I too have trouble with my sites for my pump. Does anyone take any vitamins or supplements to help with such issues? I’ve been wondering if a dermatologist might be of help with scar tissue or general bruising and bleeding of sites?

I think you’re okay as long as you rotate within reason. Pump cannulas are much larger than pen needles, unless you were using steel sets, and cause more trauma. Also it’s the repeated dumping of insulin into 1 place that causes most of the problems, not the actual needle.

Thanks for the replies everyone. This helped me gain a little better understanding of the current landscape. Lets hope for a needle free future in 10 years.

Same for me. I rotate sites and haven’t ever had a problem. Sometimes doing a LOT of daily injections seems like I should just be pumping, but either way it seems like it should be fine if you’re good about spreading the sites around.

There is never too much or too little when it comes to diabetes! If it works for you, go for it! And all I can say is rotation has been my mantra all these years. It was drilled into my parents and me so many years ago. We used every available spot we could and to this day, I do the same with my pump sites. I use any spot I can reach.

Uggh. They showed me those pictures when I was first DXd back in '83. That’s why I’ve been an assiduous site-rotator since day 1.

I think the scarring problems with pumps are not from the initial insertion but the effect of the canulas remaining in the skin for 2-3 days, leading to at least some inflammation around the site and inevitably some scarring. I think the metal sets are less prone to that as stainless steel is less reactive, but it’s really the time that’s the biggest problem. With single injections, especially with the teensy needles we have now, I don’t think there’s a scarring problem as long as you keep rotating, except maybe when you accidentally hit a blood vessel. And of course there are so many more locations you can use where an infusion set would be awkward, sat upon, get yanked out by your clothing etc.


What Scott said.

Be aware of a few things. If you are right handed, you will be more likely to inject on the left side of your body. Just be aware and make a conscious effort to rotate well.

Also, human nature is such that we can develop “favorite” spots. Try to avoid having a “favorite”.

There are a lot of places you can use. Try to be inventive and inject in many different places. I have injected in my forearms, my pectoral muscles, my calves, back of thighs, just below hips, all over my chest. All kinds of places.

Create and rotate, and you will be fine.

I am mostly using a pump now, but I have done somewhere between 75,000 and 100,000 injections in my lifetime (kinda lost count at some point), and I am doing okay.


Hello Ala,

Couple things. Do you use your legs at all? You didn’t mention using them?

Depending on what your using (not familiar with FIASP/tresbia) , don’t you run into problems with a bunch of those I assume short acting injections combining being injected too closely together time wise?

Example if whatever short acting insulin I use lasts four hours total before its off line… and if I inject a second time in that 4 hour window, the first and second injection are both active and working for some period of time, and have potential dangers caused by that fact (e.g. insulin tidal wave idea).

8-10 injections every day sounds like a lot to me… unless we’re talking micro doses???

I hope Im wrong but even with lots of serious rotating after a number of decades, not sure that some degree of lypo isn’t guaranteed? Besides it’s a whole new expression of that Saturday Afternoon Kung-Fu Movie IRON SKIN stuff…lol

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I’m not sure why the number of injections matter or how close together they are, as long as they are matched to carbs. This is exactly what pump users are taught to do. Problems can occur when the duration of insulin exceeds the duration of food digestion, but this is always a problem whether just taking 1 injection or several.

Oh I get that, I meant I’m not sure why taking too many close together in time would be a problem if they are taken to dose for food being eaten. Someone on another forum suggested decreasing the dose of additional injections to account for active insulin, but this doesn’t make sense to me unless it’s for a correction as each dose is supposed to be specific to the carbs being consumed and active insulin should still be needed unless it’s something like fruit juice which is in and out of the system long before rapid-acting insulin is finished working.

Oh, okay. That makes sense.

I was just basing my comment it on the original post which seemed to be looking at problems with too many injections in a place and scar tissue.

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The IDEA is to take the minimal injections necessary. Not three, not 5, just one if we can do it and add, subtract all the pieces just once.

Once we start taking more than one whatever the dose(s) might be they risk stacking up. The 3 units then the 6 units later on becomes 9 units in total with a bunch of overlap in time frame. Add in a couple units/injections… that overlap has potential dangers

I misread the original post and thought the question was whether too many injections were possible. Which the more times we inject, no matter how well rotated the more potential for scar tissue… IMHV. Do so for a couple decades I cant see how its avoidable in the real world, even if just to some minor degree

Disagree, there is nothing wrong with stacking if done intelligently. This is exactly what pump users do on a daily basis as well as the basis of sugar surfing using a CGM. As long as the insulin is being matched to carbs or taken for a correction there shouldn’t be any danger.

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I don’t believe it’s called stacking unless there is a correction dose thrown in there. Covering carbs for what you eat isn’t stacking. We do the iob calculations a pump does in our head if we have a correction on board.

I agree, leaving the canulas in for too long causes inflammation leading to scarring. I’m guilty of this. When I find a “good” spot for my inset I really don’t look forward to changing it so tend to leave on for 3-4 days. Dr recommended changing every 3. I don’t know if this helps but I apply vitamin E oil to my old spots in hopes it reduces scarring.

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