First Shot with Fiasp

A few days ago, I picked up the new insulin, Fiasp, brought to us by Novo Nordisk. (German article here.) Below are a few quick facts in case you haven’t heard of Fiasp yet:

  1. Fiasp stands for faster-acting Insulin aspart.
  2. Can be injected 2 minutes before meal and up to 20 minutes after, unlike Novolog/Novorapid where a pre-bolus of 20-30+ minutes is necessary.
  3. Fiasp is absorbed 2x as fast as Novolog/Novorapid, hence point 2.
  4. Contains Vitamin B3 (niacinamide) which helps with speed of absorption AND contains Amino Acid (L-Arginine) for stability.

source: Novo Dordisk Press Release dated 27 March 2017

Drum roll, please.

I have tried Fiasp twice and am excited about my results. There are however, a few quick things that I want to clarify first. I am still using Novorapid (Novolog) in my pump and injecting Fiasp via pen. In both scenarios below, I simply injected once per meal, literally right before my first bite, with no dual injections following.

Test #1 SUSHI

I felt pretty confident going into my first shot with Fiasp (no pun intended). A few weeks ago, we went to the same all-you-can-eat sushi restaurant and I bolused somewhat successfully for 120g of carbs (crap, that’s a lot). I feel like it is accurate to say I ate basically the same amount this time too. A nice controlled test. So what happened with Fiasp?


I went in with a stable 131 BG, and one hour later I was at 175, two hours after 173, and finally, three hours later I was at 236. WHAT? That was not what I expected. I am impressed with the initial relatively low spike, 44 mg/dl isn’t horrible. However, ending at 236 quite surprised me. It seems that Fiasp might be more effective used via pump, or a dual injection. It kept me stable the first two hours, but gave up when my body wanted to spike one more time. A double injection, perhaps about one hour into eating, would have been better. And for those who say I didn’t bolus enough, nope. My previous experience eating at this same restaurant tells me I bolused correctly.

*correction dose at 15:33 was given via pump (Novorapid), not Fiasp.

Test #2 Keto Porridge

Fiasp shot number two was used for Keto Porridge. I also ate this prior to using Fiasp, so I knew what to expect with carb counting. With Novorapid/Novolog, I bolus successfully for 15g of carbs (2 servings of this recipe, yeah I’m hungry in the morning). This time with Fiasp, I chose to add a dollop of Nutella, because why not? So I took enough Fiasp to cover 30g of carbs. Results?

keto porridge

Importantly, I had a stable BG before eating. Again, I took the 3 units RIGHT before my first bite. One hour after eating, I was at 88, only a 9mg/dl rise. WOW! Two hours after meal, I went up a bit to 134, and finally, ending three hours later at 154. Again, Fiasp held off spiking immediately, but ended with a raised BG. I am quite surprised with the result of the Keto Porridge experiment, as it is a low glycemic index food, minus the Nutella. I honestly was not expecting to end at 154 and I really don’t know why this happened. It could be a fluke, we all know how diabetes is. Any thoughts?

To summarize, Fiasp keeps my BGs somewhat stable for the first two hours, without pre-bolusing. However, by hour three I spike. Of course, this was my experience after only two attempts at Fiasp. I am really looking forward to more experiments, and possibly using Fiasp in my pump, as I believe a dual bolus would be more beneficial.

What are your thoughts and/or analysis of my results? 

What questions do you have about Fiasp?

Honestly, all thoughts are welcome!





  1. What app are you using to show your glucose and insulin? I’ve never seen it charted like that and I’d love to try using it. I started Fiasp yesterday and seeing some of the rapid fall-off effects AND I’m seeing that if I underestimate the number of carbs and don’t get enough Fiasp I get a fast spike and then not enough tail insulin to bring me back into range. I suspect that getting the correct amount of Fiasp right away is more critical than with Apidra AND that I may need to really shorten my insulin action time (DIA) on my Omnipod to account for this. Unfortunately, Omnipod uses a linear insulin on board approach which may not work for Fiasp.


    1. Hi 👋 I use MySugr to track my data on my phone. A quick google search will bring it up, or in your App Store. I experienced the same issues with Fiasp. And as you said, i changed the action time to 2 hours as it really doesn’t last longer unless very large doses are given. Good luck!


  2. Pingback: Novolog vs Fiasp
  3. Do you have any idea of the protein and fat content of sushi rolls? Let me say, they are not fat free – just the opposite.

    And the Keto porridge is about 51% fat. I would suggest talking to your ENDO about using the dual bolus on your pump to avoid a 4 hour after-meal spikes from high protein and/or high fat foods. They are metabolized differently than carbs.


  4. You cite the Novo Nordisk press release from 27 March 2017 for this statement:
    “2. Can be injected 2 minutes before meal and up to 20 minutes after, unlike Novolog/Novorapid where a pre-bolus of 20-30+ minutes is necessary.”
    However, this statement (or anything like that) cannot be found in the press release, nor its references:

    Click to access getPDF.2090527.pdf


  5. I am not a Dr, nor am I in the medical field but I was recently diagnosised and have been doing a lot of research since I wasn’t getting what I needed from my Endocrinologist.

    I would suspect that the reason your blood sugar levels rising 3-4 hours later is due to Gastroparesis (delayed stomach emptying). Novolog tends to peak at between 2-3 hours but gradually tapers off for 5 hours after injecting. Rapid acting insulins peak within an hour but rapidly taper off after 1.5-2 hours upon injection. I found Diabetes Solution by Dr. Bernstein to be very useful and practical information. If you get a chance I highly recommend reading it.


    1. That’s definitely not why. There are plenty of other symptoms that come with Gastroparesis which I have never had. The most likely solution is the fat content in food. When food has a high fat content, it takes much longer to break down. In this case a second injection about 30-45 minutes would have helped the later spike.


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