Relative Elasticity of Different Basal Insulins

The recent FUD discussions on the merits of MDI and pumping got me thinking about the relative elasticity of different basal insulins.

Do you think some basal insulins (whether it is Lantus, Levemir, Tresiba, etc or pumped Humalog, Novolog, etc) are inherently sturdier than others? Do you think some basal insulins are amplified by exercise, for example, more so than others?


I am fascinated to read what people will write!

For us, Lantus and Basaglar are more forgiving than any of the fast-acting insulins we have used in a pump (Novolog, Humalog). Our nights require fewer adjustments on MDI Lantus/Basaglar than on fast acting insulins on a pump. We also think we see less basal drift across the days.

On the other hand, Lantus/Basaglar do not do well with dawn phenomenon for us, and we used to have to do additional fast-acting boluses between 4-5am to take care of it. Same for sick days: very little elasticity there.

For us, Lantus reacts strongly to exercise, but not as strongly as an equivalent fast-acting insulin basal on a pump: we drop less with Lantus, and need fewer carbs (but still a lot).

We have little experience of Levemir, and no experience of other basal insulins.

Incidentally, Lantus/Basaglar is good for 24 hours for us (we use 14-20U of Lantus per day).


For me, fast-acting insulin in the pump has been, by far, the most sensitive to exercise. I think Tresiba and Lantus are comparable. I feel like Tresiba might be more sensitive than Lantus, but I’m not entirely sure about that. The sensitivity is similar enough that I’m not confident about making a solid statement on the difference between the two.

I think Tresiba is more consistent than Lantus, and I’m able to get much better results on Tresiba.

My basal needs vary a little bit. I seem to need less basal in the early morning hours and more basal in the late evening hours. Despite that, I think my control is better on MDI than a pump. I think the pump introduces more variables and ends up complicating the situation. It may be that my body simply doesn’t absorb insulin as consistently as other people’s. In any case, I think having a consistent basal insulin enables me to predict the effects of all the other factors a bit better. I’d rather work around the known problems with Tresiba (namely, not being able to change my basal rate easily), than jump through all the hoops of a pump. I feel like a pump introduces all these variables that interact with each other (poor absorption, bad sites, varying basal rates) so I had trouble predicting things while I was using one. It was also a lot more work, and I had to carry all this bulky crap around just in case my sites failed.

My basal needs are flatter than some others on this forum though, so that may be why Tresiba is less work and a better fit. So of course, I think Tresiba is the “sturdiest.” :slight_smile:


Yes. I think all of the above.

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Exercise has minimal effect on Levemir’s absorption, because of the way it binds to the albumin in the blood.

Exercise has a greater affect on the absorption of Lantus, because it uses the body’s pH to affect its action. So there is more site variation.

All of that being said, exercise will affect any insulin action, because even if the absorption is not directly affected, exercise will stimulate the expression of the GLUT4 glucose transporter in the muscle tissue.

So really, exercise is going to affect any insulin action, regardless of how it is absorbed.

In other words, while the absorption may or may not be affected by exercise, the exercise itself makes any insulin in your body more powerful.

Here are some useful resources. Go to the Pharmacokinetics section of each for a discussion on absorption. But the entire document is useful for each.


Great information, @Eric. Thank you!

Do you (or anyone) think that the “sturdiness” of different basal insulins would be different under the varying effects of: stress? hormones? grief? relaxed sedentary time on vacation?

I’m just trying to think of a variety of situations/conditions that could influence the efficacy of basal insulin…and if it would hit them all similarly or not?


At some level it appears that you are asking is there a difference in the different types of insulin when insulin resistance changes? i.e. stress and some other factors that affect your insulin resistance.

I don’t actually know the answer to it, but it is a fascinating question.


I do not believe that those things affect the type of insulin differently.

Yes, all of those factors affect our insulin sensitivity, but the type of insulin doesn’t matter because after a basal insulin has unbound or unwound or been absorbed, insulin is insulin. It does the same thing. It binds to the tyrosine kinase receptor in the cell and signals the GLUT4 transport.

The cells don’t care what type of insulin it was to start with. To them, it is all the same once it gets to the cell.

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That’s the real question though I think, is the absorption mechanism affected in a meaningful way by all the variables she lists above. I agree insulin is insulin once it gets to the cell receptors, the million dollar question is what variables effect how consistently end efficiently it gets to that point, and how does it vary between the different absorption mechanisms


Someone may be able to distill what I’m about to say in a clearer, concise question…but I’m going to brain dump it here to try to get there myself:

I have to change how I dose Humalog for meals based on a million factors. Humalog, from my perspective, is somewhat volatile based on how one dose in one situation is great and using the same dose in a different situation is just asking for tons of trouble. I’m not bagging on Humalog (really, I’m bagging on T1D). I’m just observing the number of factors that influence my body’s ability to make use of it in different scenarios.

For me, Novolog was very crisp…but it seemed to have a much smaller margin of error for me. In other words, the percentage of bolus changes I would make for a meal with Humalog for expecting to be sedentary after a meal would be way too much using Novolog.

Beyond that, thinking of fast acting insulins for basal vs long acting insulins for basal…maybe @Sam has had such a good run with Tresiba because it isn’t as amplified by exercise/stress/inactivity/etc? Or maybe his basal needs really are less variable than others?

I haven’t doubted @Sam’s testimony of his experiences on other threads at all. But it does make me wonder about if different insulins show different stability through varying conditions.

@Eric may have already answered this question with his information above.

What I liked about MDI was that there was only so much that I could change. There were pitfalls, but I could plan around those to a palatable extent up until I went off of birth control. Once I went off of birth control, Lantus’ tendencies and properties no longer met my safety needs for a variety of reasons. But that doesn’t change my intellectual question regarding stability through various conditions impacting insulin sensitivity.


I think exercise would affect the physical absorption of insulin. And also temperature, things like a hot shower or whatever.

But I personally don’t think stuff like stress or hormones has much affect on absorption. That’s just my guess. I think the insulin resistance caused by different hormones has a much bigger impact on insulin than any absorption issues we might see.


FWIW, my experience matches Eric’s summary. When I was taking NPH or Lantus as basal insulin, I would sometimes use exercise to amplify my insulin response and bring my BG down. Rather than injecting a correction bolus, I would run, row, or play squash until my BG came back to normal.

Levemir does not have that affect to nearly the same extent, however. I will leave for a 10K run, and assuming I have no bolus insulin onboard, My BG will usually go up 20 or so points for the first 5K, then come back down plus a little more for the second 5K. This is pretty predictable (to the extent that T1 is ever really predictable).

I haven’t had the chance to try Tresiba yet, so don’t know about that one. But based on Sam’s experience it sounds like this is also stable across exercise.

Maybe this is another instance where MDI is easier to manage than a pump. I was surprised by how complex it was in the DM and DN threads to manage exercise around a pump (reducing basal some hours before exercise and taking carb before and then bolusing afterwards). While using Levemir, I simply put on my shoes and go, with no preparation necessary and no real cleanup afterwards either.


Very good description. I also can take off into pretty vigorous exercise with tresiba as long as there is no bolus on board and not fear much of anything to happen during or after. This is my concern about rapid through pumps, they are incredibly adjustable, but they ~require~ that incredible adjustability by their very nature from everything I’ve seen. My basal dose would equate to approximately 1u/ hour if it were on a pump. I would bet the world I couldn’t take off on a 10k run with that insulin coming from a pump like I can with it coming from tresiba without an elaborate ritual of adjusting before and after for several, maybe many hours afterward. Everyone will say I can’t possibly know that because I haven’t used a pump… but I think I’ve certainly used enough rapid insulin to observe its characteristics for me…

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I’m on a pump, and based on using rapid insulin’s for basal, Fiasp is by far my favourite. Very rapid and consistent. I used to get hours-long highs that needed many, many corrections to get down. With Fiasp, generally I do one correction. If one correction doesn’t work, it usually means a new set is needed.

I’ve also used both Humalog nad Apidra in my pump. I didn’t notice much difference between those two.

For basal insulin’s, I’ve used Lantus and Tresiba (briefly). I would say out of those two, probably Tresiba was the most stable, BUT I preferred Lantus because it was more adjustable. With both insulins, I had periods of highs and lows and could never find a single dose that allowed me to be truly flexible. Exercise has seemed to always lower my BG substantially, regardless of using a basal insulin or pump.

I’ve also used Regular and NPH, but that wasn’t really with MDI, so I can’t comment on them. On that regiment, though, my BG was all over the place.

I’m interested in getting ahold of Levemir as my backup insulin. I’ll probably ask for a prescription for it when the Lantus and Tresiba in my fridge expire. Lantus only lasted for 20 hours in my case, so if Levemir lasts for 12 and is as consistent as Fiasp is, then this could be a. Great insulin for periods when I go off the pump (which I do from time to time for 1-2 days if I get sick of it).

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Yes, you do have to go through an “elaborate” ritual on the pump. For me it takes all of 4 button pushes to turn off basal before a run. Pretty elaborate. :roll_eyes:

I won’t argue that rapid insulin absorption is affected more by exercise than an analogue basal.

But at least you can adjust it on a pump. You can’t do that with analogue basals. At all! Once it’s injected, you are stuck with it for the duration.


I hated intense exercise with Lantus. Felt like I’d crash for days afterwards, no matter how much carb I had before, during and/or after. But if I just sat around, Lantus was beautiful (barring DP and afternoon slump).

I find sporadic bursts of exercise, no matter the duration, are so much easier to handle with just pumped Humalog (but not Fiasp, no way), with no “elaborate ritual of adjusting before and after.”


See, there probably is no real answer to this question. Because one of the variables is that insulin works differently for different people… I love Fiasp, but you and @Eric weren’t fans. Some people find Lantus lasts a full 24 hours (or more), others like me find it doesn’t last 24 hours… It’s hard to compare things when the individual itself is a variable!


Fiasp worked okay but it left really huge welts at the infusion site. So that is why I was not a big fan of it in the pump.

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Love all of the different comments on this topic.

FWIW, I used to need a 45% increase in my Lantus to manage peak hormones. Pumping with Humalog, I usually need 25% extra max these days. Sometimes 30%.

Tons of variables in there…but that is with years of observation and tracking.

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I can’t add much when I’ve only done Lantus/Basaglar and a pump . The pump thing didn’t work due to constant failures and I could not be flexible on it when it somehow did work once in a blue moon because if I did? Pumped novolog acted like a mealtime dose or correction a lot of the time I used it… and made my blood sugar drop like a rock, I didn’t even dare to do much activity while on that since I knew exercise+insulin may not be the best thing at all times. I have a physical job now , I lift people (I’m a CNA), I do a lot of walking, I do some otherwise similar to exercise tasks at work (lots of bending, reaching, heavy objects that aren’t people , etc I don’t sit down much for 8 hours) and so far Lantus/Basaglar has never made me just go low out of nowhere. Only thing that makes me low out of “nowhere” is if I mess up on mealtime insulin. Pretty sure that’s the case at least based on what I’ve figured out through testing and just overall how I feel at any given time? I mean I’m gonna try to get a gym membership soon to work off some extra pounds/combat the holiday food weight gain if possible , so I may get a different perspective with true exercise but …pretty sure I used to do that before with lots of walks, sit ups/push ups and whatnot before having such a physical job.

I also feel like it’s very sturdy to me, but I haven’t tried levemir, toujeo, or tresiba. I feel like Tresiba would be very sturdy and for sure get the 24 hours and keep you pretty stable out of all of these though, but that’s just guessing without using it.