Review of FiASP insulin and how it compares with other fast insulins

//Review of FiASP insulin and how it compares with other fast insulins

Faster Insulin: The Holy Grail of Type-1 Diabetes

OK, my kids are right.  I’m a geek.
Monty Python movies still crack me up… especially Monty Python and The Holy Grail.  Love that scene at the “bridge of death” where the creepy guard asks questions that must be answered correctly in order to pass, lest you plunge into the bottomless gorge.  Challenging questions like “what is your name, what is your quest, and what is your favorite color.”


In the diabetes world, the answers to get to the desired insulin treasure are a bit intriguing.


What is your name?  “Just call me ‘tired of waiting for this so-called-rapid-insulin to work.’ ”


What is your quest?  “I seek a faster insulin.”


And what is your favorite color?  “Whatever damn color the faster insulin is, that’s my favorite.” 

Well, our quest isn’t quite at an end.  But we’re getting closer.

Here’s my review of FiASP insulin and how it compares with other fast insulins:

Novo Nordisk’s new FiASP insulin (short for Faster insulin Aspart) has hit the market in various parts of the world, and is awaiting FDA clearance here in the US.  The good news is that it IS faster than the rapid insulins we’ve been using for the past 15+ years (aspart, lispro, glulisine – brand names Novolog/Novorapid, Humalog, Apidra).  The bad news is that it is just slightly faster, and still nowhere near as fast-acting as the insulin the pancreas produces.  It’s also not quite as fast as inhaled insulin (Afrezza) or injections of rapid insulin given into muscle.

But it is an improvement.  By adding niacinamide to the formulation, the insulin molecules form monomers (single pieces of insulin) that move through the subcutaneous fat layer faster than before.


How much faster is FiASP as compared to normal insulin?

Its onset of action is about 6 minutes earlier, the peak is 7 minutes earlier, and it works 50% harder during the first 30 minutes compared to traditional aspart.

The result:   Better post-meal patterns with a peak that is approximately 40mg/dl (2.2 mmol/l) lower. 


What about the duration of action?

Sorry, no difference.

It takes just as long to finish working as the rapid insulins that are currently on the market.  Although it starts out faster, FiASP has a long tail of action.  However, when used to correct high blood sugar, you will notice a more rapid decline during the first 30-60 minutes.

Will FiASP be approved for use in insulin pumps?

Yes, but beware:   The “insulin on board” algorithms will be rendered somewhat inaccurate.  Those algorithms are based on the action profile of traditional rapid insulin, so when using FiASP, the pump will over-estimate IOB during the first two to three hours.  It may be necessary to set a slightly-shorter duration of insulin action in order to have the pump calculate IOB correctly (for example, setting 3.5 hours rather than 4.0 hours).


Does dosing need to be changed when converting from rapid-acting to FiASP?

Unit-for-unit, FiASP has the same potency as rapid-acting insulin, so it should be a relatively easy conversion, and one that I would recommend to most people on pumps and multiple injection programs.  However, don’t fall into the trap of thinking “this stuff is faster… I don’t have to take it ahead of time.”  That’s like buying reduced-fat snacks and then eating the entire package because they’re… well… better for you.  Users of FiASP will still need to pay attention to the timing of their bolus insulin.  In order to see the benefits of the faster onset, it will need to be taken at the same time you take your insulin currently.  Taking it later will negate the benefit.  And with slowly-digesting meals/snacks, it will be more important than ever to delay the injection (or use a dual/combo bolus) in order to prevent post-meal hypoglycemia.

Bottom Line:

So at least we’re on the right track.   Much faster insulin is going to be necessary if our “hybrid closed loop” systems are ever going to become full closed-loop systems.  But for now, an almost Holy Grail is better than no grail at all.

By |2017-06-21T17:41:35+00:00June 21st, 2017|Thinking Like A Pancreas Blog|31 Comments

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  1. John June 21, 2017 at 8:47 pm - Reply

    Hmmm… Well, I’m not quite as excited about FIASP as I thought I’d be. Sounds like getting highs down quicker is the best part of it. Should lead to more time in range. More trial & error to come! Thanks for posting the review!

  2. Liz Brownlee June 22, 2017 at 10:31 am - Reply

    i’d take issue with some of this. i’ve been using it for the last 2 months. It works immediately – and i mean immediately. I had to change the period of action on my pump from 4 hours to 2 and a quarter hours. It tails off much more quickly. It’s fabulous – my after meal highs are GONE. The only meal which this is not true of is breakfast – hormone-induced highs seem impervious, i deal with this by giving myself a correction on waking and a third of my breakfast insulin. Then the rest just before breakfast. This works. NOTHING has ever worked before. You are warned not to take the insulin any more than two minutes before a meal, and i have found longer than 5 is a problem.

    For me, it works as fast as i would like it to work – any faster I think would be a problem!

    Have you tried it?

    • alicia downs October 16, 2017 at 7:44 pm - Reply

      Yes everyone here at IDS have personally used Fiasp. none of us found the quick onset that you did. But anytime someone finds themselves outside the norms of insulin action they should adjust their therapy to their needs. Glad you’ve had success with it, and that you are making it work for your needs.

    • Ron October 18, 2018 at 9:24 pm - Reply

      Just started and I agree with Liz

  3. Mike (everydayupsanddowns) June 22, 2017 at 12:04 pm - Reply

    Thanks for the review. Really interesting to get your opinion on it. I’ve been using Fiasp in an insulin pump for a few weeks now, and I have to say I find the differences of action between Fiasp and NovoRapid to be much more significant than you are suggesting here. It’s quite early days for me, but I have been wearing CGM to observe the differences. I am still gathering data, but early signs are pretty promising. I absolutely agree that it is nothing like instant, but I am able to make adjustments to my approach to various things with the benefit of the significantly shorter onset. Here are some examples:

    Meals for which I would have needed 30-45 minute pre-bolus now need only approx 10-15 minutes.
    The ‘significantly faster to peak action’ means boluses for more rapid acting carbs (eg white bread) can be taken just before eating and give reduced BG spike post-meal.
    Corrections with NovoRapid which often showed little effect for the first 60-90 minutes are now beginning to reduce BG within 30-40 minutes.
    Moderate carb load meals (eg basmati rice) which Novorapid ‘matched’ in absorption/action profile now need careful dual wave handling to avoid post-meal hypoglycaemia at 60 minutes.
    Duration for me seems to be about 25% shorter than NovoRapid – though of course it is always difficult to spot exactly when the tail is ending.

    In short my n=1 is that it the difference is significantly more than 6 minutes/7 minutes earlier action suggested.

    I’d be interested to hear how others have been finding it.

    • dino December 1, 2017 at 1:35 am - Reply

      great insight. wonder what you mean about the dual wave suggestion (with moderate carb load meals) to avoid hypo at :60. I’m using fiasp currently, and finding that I’m going hypo at that time with exactly that kind of meal,m

  4. Scott June 22, 2017 at 8:12 pm - Reply

    Thanks for the review Gary. Although a little faster action sounds good, I’m sure this insulin will still carry a hefty price. I would be more excited if the rapid acting insulin manufacturers would deliver on better pricing at this point if no new breakthroughs in therapy are emerging. I will be dealing with Medicare very soon and when you hit that donut hole in coverage, it is very scary to make it through to the other side of the donut hole and still be financially solvent!

    • Pat Tennies March 7, 2018 at 4:33 am - Reply

      If you have an insulin pump, Medicare will pay 80% of the cost through part B. It is considered durable equipment. You don’t have to worry about the donut hole. If you do not have a pump, then your drug plan pays. Good luck with that. You will hit donut hole soon. They may not cover it at all if not on their formulary. I did read that it will be the same price as Novolog.

      • Dave May 19, 2018 at 5:54 am - Reply

        Pat Tennies: Medicare DME won’t pay for Fiasp in the US because it hasn’t been approved for pump use………yet. I’ve been fighting with Medicare, Noridian, and Walgreens for 2 weeks and have lost the battle twice even tho’ my endo put me on it a month ago. I have achieved 50% better control the last month. Guess I’ll just have to go back to using Novolog until Fiasp gets approval for pumps. Hopefully sooner than later.

  5. Tara O'Hara June 23, 2017 at 12:20 am - Reply

    What niacinamide and what kind of long term effects does that have?

  6. Jennie Dyke June 23, 2017 at 10:04 am - Reply

    Thanks Gary!

  7. Tim August 9, 2017 at 6:59 am - Reply

    My experience of Fiasp is rather different from what you’ve written above. I (and quite a few others) have found that we can take it immediately prior to eating and experience very minimal post prandial rises in blood glucose, indeed, I have tested in with a fairly boring white bread and jam meal, with an immediate pre-prandial dose, and found no rise in glucose levels.A fair number of people have found that bolusing as you would with normal fast acting insulins results in hypos very soon after eating. As always, your diabetes may very, and not everyone sees the same effects.

    It seems that the faster onset is not the critical factor in the way this insulin works, but rather the larger availability of insulin in the first 30 mins, which seems to have a major effect. If you’d like more information, I’ve written a lot about it here:

    The other thing to note is that the duration is the same as that of Novorapid. Whilst the curve shape is slightly different, i.e. there is less insulin on board between 3 and 6 hours, it’s very much still there, and setting a pump DIA to 3.5 hours will significantly underestimate this factor out at these times.

  8. SB2015 August 20, 2017 at 10:05 am - Reply

    Thanks for the review. I have switched but I am only three weeks in.

    As suggested post meal spikes are smaller and have become blips on meals of less than 30g CHO. For bigger meals it is a lot less predictable.
    It stings when delivered. I tried extending to 15 min but that just prolonged the stinginess.
    Cannula sited need changing more often, now diong on his daily rather than every two days
    I have reduced the timing before I deliver before meals but reading your review I shall still look at these
    It is a lot better when eating out and I need to wait until the food arrives to deliver. It comes down more quickly than before
    As said correction work more quickly.

    I have decided to give it a proper try and do at least three months. The benefits need to outweigh the stinging in delivery.

  9. Deidre Waxman August 26, 2017 at 5:27 pm - Reply

    I picked this up in Canada last week. I’m very disappointed. I see almost no difference between Fiasp and the usual suspects . I was so excited to try it but for me it’s been a dud.

  10. Rob September 10, 2017 at 12:20 am - Reply

    Medicare saved me money on my insulin. I use a pump, which makes insulin covered by part B, not Part D, of Medicare. With my Plan G supplement insurance, after I meet my annual deductible of about $166, my insulin has no out-of-pocket costs.

  11. Al October 10, 2017 at 4:33 pm - Reply

    Afrezza is faster in & out..and it is shot

    • alicia downs October 16, 2017 at 7:29 pm - Reply

      very true, Afrezza is pretty amazing at its speed. But, it’s not for everyone. There many people who can not get the tight dose control needed, or who have respiratory issues. Fiasp gives them a great new option.

  12. cherril October 11, 2017 at 1:22 am - Reply

    Unfortunately I’m not noticing much difference. Huge spikes of 14 or so if I take it with a high carb meal, with 2 or 3 extra boluses required over the next 2 hours to fix it all. I’m sad. Nothing has changed…

    • alicia downs October 16, 2017 at 7:32 pm - Reply

      Getting the right strategies to cover meals can be really frustrating, particularly when you don’t have a guide. Insulin management is all about timing. splitting meals, splitting dosing, prebolusing and use of advanced pump features are all methods that we teach at Integrated Diabetes Solutions to help our clients get the best post meal management they can. Give us a call and we can work with you in this area. 610-642-6055

      • Dawn Papp July 11, 2018 at 1:38 am - Reply

        Alicia Downs, my doctor has given me FIASP to try and I haven’t had good post meal numbers majority of the time. What do you charge to help clients with insulin management?

        • alicia downs August 29, 2018 at 2:05 pm - Reply

          Hi Dawn,
          I recommend giving our office a call. 610-642-6099. One of our office staff can walk you through our services and pricing. WE look forward to working with you!

  13. NoraWI October 13, 2017 at 2:40 pm - Reply

    Since pumps also deliver basals, how does fiasp’s faster action affect basal dosing?

    • alicia downs October 16, 2017 at 7:34 pm - Reply

      great question. There is no adjustment needed to basal dosing with Fiasp. Since basal dosing with a pump is a series of micro doses over 24 hours, those doses are designed to overlap in action. This is actually why basal insulin dosing works. So the change over to Fiasp requires no change at all to basal dosing or timing.

  14. Ali December 21, 2017 at 4:51 pm - Reply

    I have not tried Fiasp but I do use Apidra and I do find it to start much more quickly than any other insulin and importantly to finish working much sooner. The tail of all the other insulins caused me issues. What I find interesting is that most people do not find a difference in the insulins while some people do find Apidra and Fiasp to work more quickly and at least for me with Apidra to have a shorter tail. What would be interesting to research is why? FWIW have been a T1 for almost 50 years so have been on all the different types of insulins for several years, never just a short few days or weeks and also have used all the fast insulin in a pump and with intensive BG testing either fingersticks or CGMS. So again accurate data generation. I do have to adjust my basal rates with the different insulins. I would not switch to Fiasp if it had a longer tail than Apidra in my system.

  15. Brendan Hyland December 29, 2017 at 3:56 pm - Reply

    I believe it’s a good option. For me though for perfect glycemic control it’s Afrezza everytime. The problem with FIASP is that it hangs around too long. Afrezza clears much faster and flat blood glucose profiles are possible with minimal effort. I love Afrezza.

  16. Stan Silverman March 15, 2018 at 2:35 pm - Reply

    Has anyone had any experience with Fiasp with 670G and Guardian 3 system? I’ve been on this since early December. Generally doing well but I was hoping to see a better HgbA1C. I was thinking of trying Fiasp to bring down my postpradial highs. I’d be interested in other’s experinces. Also, trying to decide when I try if whether to change my active insulin time from 4 hrs to 3.5.

    • alicia downs March 29, 2018 at 5:08 pm - Reply

      Multiple educators at IDS have been using Fiasp. The most important take aways are that it is not a replacement for prebolusing, it is a supplement to it. To not prebolus makes fiasp the same as novolog with a prebolus. The second take away has been that the full 4hour action time of Fiasp is the same as the 4 hour action time of novolog. so shortening the DIA tends to increase post correction lows.

  17. Dee August 27, 2018 at 1:02 pm - Reply

    I have used humalog in my insulin pump and opposed to Fiasp I have seen a big difference in my blood sugars with this faster working insulin.

  18. Gaynor Giles September 1, 2018 at 2:02 pm - Reply

    I am prone to weight gain – 3 stone with apidra. Doing weightwatchers so not down to my diet. It is listed as a major side effect for fiasp. Has anyone actually experienced weight gain on it please?
    The only insulin I have found which does not do this to me is porcine- which I currently use in my pump. My DSN would like me to try it and I am keen to have better control but want to find out more about weight gain.

    • Gary Scheiner November 11, 2018 at 3:39 am - Reply

      ANY insulin can cause weight gain, particularly if you are experiencing frequent bouts of hypoglycemia. If your glucose control has tightened, you are simply urinating away fewer calories than you were previously. If you would like to set up a consult with a diabetes specialist who is an expert at helping insulin users to lose weight, feel free to contact our office manager for more details:

  19. Bonnie Stillwell October 23, 2018 at 7:10 pm - Reply

    I have been on Flasp for 2 days now and have had highs for this period of time. I have had highs thru the night although I am bolusing and during the day, same thing.
    It’s like i’m taking water! Every unhappy.

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