FIASP for Insulin Pumps


I thought it might be helpful to post images of a “typical” day on Fiasp vs. a “typical” day on Humalog. As you all know, there really isn’t any such thing as a “typical” day as it seems that every day is different so maybe “representative” would be a better term to use. In any case, I think you will get the gist of how Fiasp is working for me vs. Humalog. I’m posting 2 screen captures for each… The daily CGM curve from my Tandem t:slim X2 pump which also shows the pump calibrations. The “gap” on the Fiasp one is where I had to do my weekly CGM sensor change.

Here are the Humalog screen shots from Glooko Diasend reporting application:

Here are the Fiasp Screen shots from Glooko Diasend reporting application:

You can see from my basil rates for both Humalog and Fiasp, that I have a multi-tier basil program and have developed that changing rate over time based on my body’s need for basil insulin at various times of the day. I did have to tweak it for the Fiasp and that is why the blue line looks different on the two.

One thing to also note when viewing these is that I don’t eat breakfast. I found that breakfast would start me on a YoYo where I was chasing the ups and downs for the entire day. Now that I’m on Fiasp with significantly reduced post meal peaks, I may try to going back to eating breakfast. I’ve been on the “no breakfast” routine for several years now and I have the basil pretty well tuned so that things stay pretty flat until I do lunch… Usually between 11:00 and 11:30.

You will also notice one “oops” at the end of the day on the Fiasp day. I had a snack and over estimated the carbs and that drove me a bit low.

You will also notice that I was “chasing the high” on the Humalog day and had to do multiple correction boluses after dinner. I also did my boluses well in advance of eating lunch and dinner and still had the significant peaks with the Humalog.

As I have stated, Fiasp has been truly a game changer for me. It may be that my body physiology is just a good match for how Fiasp works and I may be the Fiasp poster child so your mileage may vary :slight_smile:



Is there any way you can split up your carbs a little, maybe a mid-morning and afternoon snacks? Since splitting my former breakfast between breakfast and an early morning snack abut 6 wks ago, I rarely have low/high BGs or stubborn highs before lunch. And my weight is down 7 lbs as that change has mostly eliminated high fat morning peanut butter snacks.

I couldn’t have made the change in my previous Air Force position. Supervisor wouldn’t have allowed and only for her own convenience.


I am on day 24 of Fiasp now.
I have still been trying to test it out on random foods.
I have found that I have made a few bad guesses… Oh well.
BUT, even those bad guesses have been FAR more controlled with Fiasp then Novolog.
I left all pump settings alone except time down to 3.5 hours. I am still using these settings, but I am thinking I might start lowering my daytime basals.
Right before starting Fiasp, I was about to raise my nighttime basals a little more. But now they seem pretty on target. Might even lower the basal a little around 4 to 5am.
Point is, because of the way it works, I will use less for my basals, which is a big win for me in many aspects.

Now, I have had some BIG meals. Like an entire large frozen pizza! First time I did it, I didn’t get it right, but all things considered, it went well. Second time, you would barely guessed I ate a few carbs!
I hit it harder, and hit with a second dose for fat/protein.

Two downsides for me.
First, it stings/burns sometimes when I bolus. Mainly larger boluses. I am not worried about this, as I don’t have a sight irratation issue. I have even left the sites in for 4 days a couple times now.
Second, I CANNOT pre-bolus! I did it once to make a correction and bolus before eating a somewhat higher carb lunch. Not a good idea! I dropped like a rock! Lessons learned is to only do the correction, then bolus when actually eating.


I might be weird, but I find some amount of comfort and/or peace of mind when I can feel the insulin going in from a bolus. I suppose it just helps me know that it is going in and not leaking or failing to absorb.


I am not really complaining about the sting/burn. But I thought it was worth mentioning for people that it would be an issue for.


Not a bad suggestion, though in my case I don’t actually eat breakfast as a rule–just coffee; a lifelong habit, hard to break.


@DrBB - I have been wondering the same thing.

Have you picked up information on this particular aspect?

As well, what is the actual effective gain in speed of the Fiasp via pen vs the Novolog/Humalog via pump? Often times I read about how Fiasp starts working in xx minutes which from my point of view is pretty useless information. The way you phrase your question makes more sense for me.

very long pre-bolusing time, like an hour to an hour-and-a-half, and long, persistent post-prandial spikes from relatively moderate carbs because it’s so hard to get the insulin going early enough

So if you were to use Fiasp via a pen, how would this particular situation change? If you do run a trial, I would be very interested in hearing what you have to say. The way I look at it, this removes the ambiguities of “when it starts” and “when it peaks” and all that which is interesting from an academic point of view but at the end of the day it really comes down to “how long of a pre-bolus do we need” as it compares the Novolog/Humalog in a pump to the Fiasp in a pen. If that is what we are interested in looking at.

Which we could try but if you happen to try it first - well - I would love to hear what you have to say.



I guess I was thinking about something my DBE said about pumps in some cases having slow delivery speeds and that that affected how quickly FiASP could go to work. I’ve currently reverted to my old pager-style Paradigm pump (only 3 clicks to suspend instead of 10-plus-a-confirmation-screen with the 670, grr). But one thing the 670 has is adjustable delivery speed, whereas my old pump is hardwired very slow. A big bolus can take a minute or two to finish. Haven’t heard any responses about the question though.


I may see if I can talk my T1 into giving this a try.
(ie - mostly pump usage with occasional Fiasp pen for certain bolus)



Spreading out carbs should also work during the day.


Honestly, if I tried, I can easily go back to smaller low carb meals that use very little. I would probably have an almost FLAT LINE if I did.

I am just trying out different things to see if/how it reacts. And, well, to enjoy eating some foods!

And I know that my time is still far too short to tell if it will continue to work. I know some people used it for some time before it stopped working.


Shoppers Drug Mart quoted me $37.79/vial Canadian and no taxes. Not in stock, but two-three days to bring in as a special order. I’ll be picking up three vials tomorrow in person.


I already placed an order for 7 vials from Mark’s Marine Pharmacy in Vancouver, CA. It is a brick and mortar drug store who ships to the us. The cost was more, at $70 per vial, but far less than the US $289 per vial, if not covered by insurance.

Regards, Steve Yarbrough


Well, I finished my two vial test run of Fiasp.
I use the Tandem X2 pump with Dexcom CGM.
I already have pretty decent control of things, but with Fiasp, I not only had more time in range, but I did a LOT better on the spikes and drops within that time. So my Quality of Life rating for Fiasp is FAR higher than Novolog was.
I am back on Novolog today, and I can already tell the difference in the time frame it works, how well it works, and most importantly, how I FEEL.

Now, I just need to find the least expensive option for ordering this. I imagine that the VA will eventually supply it, but I will not hold my breath.


I stopped my trial of Fiasp after 8 days. I definitely did see a faster start-of-action with it (though perhaps not as pronounced as you?) My results from higher-carb meals were mostly pretty good though I did have one hard-to-control spike near the end.

What I did notice, however, was that while it starts working faster than any of the other insulins for me, it takes a lot longer to tail off than Apidra – it’s more like Novolog in terms of the tail. For me, that meant that I had periods of time when I felt ‘uncomfortable’ – like I was having a hypo, even though my BG was well in range (or even above). I get that feeling at times when my BG is dropping somewhat quickly, even when high, but this was even when it was seemingly stable. I’m back on Apidra just one day. and already that feeling is gone, so I’m fairly sure it was Fiasp-related. I’ll probably give it another go sometime later, but for now, I’m more comfortable with Apidra.


I get my first vial of it day after tomorrow (had to wait for my current insulin script to be refillable). Feeling cautiously hopeful…


I understand what you are talking about with the ‘feel’ of the tail being different. Although I was on novolog before, I still noticed a slightly different ‘feel’ to it.
Also, I started this on Novolog, but I raised my target number from 100 to 110 to be more aggressive with my dosing and still not go low.
This actually carried over real nice to Fiasp. I wasn’t dosing nearly as aggressive, but this actually worked better for me than changing my time on board.


I’ve been using fiasp in my pump for about 2 months. It works much better and faster than novolog, which I had been using for years. The drug info says it’s only 5 mins faster, but I can see the impact (on my cgm screen) almost immediately. On fiasp, I’ve noticed that it’s really important to change your site every 2 days, and avoid placing the infusion set in places where there is a lot of fatty tissue. I’ve not had any skin irritation. My endo was very willing to prescribe it. I recommend calling around and asking potential new endos about their practice’s willingness to try “new approaches” to managing T1D and their creativity in addressing problems. That may help you find someone who will write a script for you - it’s probab going to be awkward to directly ask about fiasp for the pump.


Why is that exactly?

BTW, I just started pumping Fiasp two days ago. First day, I didn’t notice a big difference but last night we had Chinese (my granddaughter’s b’day; her choice) which for me ranks second only to the dread Pizza itself for being unpredictable as regards bolus estimates and for producing correction-resistant spikes. Fiasp stopped it dead in its tracks–post prandial BG maxed out at ~120, which is astonishing. Though I did run into some overnight lows, so I may have over-bolused a bit. And I suspect some basal adjustment is in order.


Because of its long tail and the way that made me feel, I’ve stopped using Fiasp in my pump as my primary insulin. That said, I still have some, so I’ve decided to use it for corrections. Yesterday, my local “Summer Begins” moment occurred when the small neighborhood ice cream stand opened. Took my family - and had a milkshake myself (not far behind pizza and Chinese for challenging!). Took a pre-bolus from my pump (Apidra; about 10-min), and followed it with a small correction on Fiasp via injection after Dexcom turned to :arrow_double_up: – End result: Spike did get to 168, but stopped there, turned around and landed safely at 88. Pretty big win to me.