Humalog to Novalog

I need the scoop on differences between Humalog and Novalog, please.

My insurance will no longer pay for Humalog, not even with a larger co-pay (what they used to do).

I’ve used Humalog forever, but never Novalog. And I am MDI. Thanks!


I didn’t notice any difference between the two.


It is the same for MDI. No worries for you there, really!

I used Humalog every day, from the first day it was released until about 4 1/2 years ago. And then I switched to NovoLog (I still do some shots with Humalog on occasion, but not much).

No difference with injections!


What about wait time until eating? Some sites say only 5 minutes for Novalog, and 15-20 for Humalog. I usually use about 20 minutes if I’m where I want to be, and longer if I’m high BG.


Ultimately the only way to know about time differences is trying it out, because those times you mentioned can be the result of marketing material or testing that was performed differently - like if they do a euglycemic clamp study or who knows where those numbers came from. Maybe they said 5 minutes because they freak out about making someone go low!

For me, pre-bolus can be any crazy number, depending on a million things that are involved. Like I would never say it is always X minutes, it just depends!

The only difference I noticed is in a pump. NovoLog is more stable over several days and Humalog craps out much sooner.

But at least for me, with injections they are interchangeable.

I don’t think you will have any problems with the switch. Just start it the same and see how it does. If necessary, you can make adjustments.

Restating because I think this is the important part -

I think you are better off making the switch doing it the same way as you do now, rather than trying to read what some unknown study said and adjusting based on that.


One small data point here, I was super sensitive to Novolog the first month that I used it when I switched from Humalog, and then my sensitivity settled down to similar levels the second month.

But there was also a question about me becoming allergic to Humalog so I might be a super outlier here.


I’m working on pre-bolus time, and a couple of times I’ve gone really low (like 40-50) after eating breakfast. It was about 45 to 90 min after my shot. I was low range BG to begin with, and thought I was conservatively dosing. I don’t know how long the pre-bolus time was (I didn’t write it down). Did I probably wait too long?


This has been my experience. Last year my plan switched to humalog. I did try humalog (in pump), but found dosing was different, and humalog just kicked in slower, less predictable. I probably could have changed my dosing calcs/eating timing, but currently using a cash pay discount card for novolog.
It actually turns out costing less than what would pay for humalog under insurance.


When I am low or dropping, I sometimes take my insulin after I start eating. The pre-bolus time really isn’t always the same for me every time, it just depends.

In that situation you described, probably taking less AND taking it a little later would have been the way to go.


I’ve been using Novolog in my pods for a month and a half. I never had any problem with Humalog in the pump, not even by the third day of a pod, but decided to try Novolog just to see if it was true for me what people here were saying, that it was more stable, more predictable. I don’t know if those are the words I’d use – I mostly find it just evens things out more than Humalog. If I’m going to go high, I don’t go as high or for as long. I’ve gone from January’s 75% TIR and 14% high to March’s 86% TIR and 7% high. I’m sticking with it now.

Note that Novolog is my basal and my dinner bolus insulin, half injected, half extended. For breakfast and lunch boluses I inject Fiasp.


I didn’t notice a difference, but my insurance went from Novalog to Humalog. My doctor initially put me on Novalog when I was on the pump. Said it flowed better than the Humalog.