Trying #Fiasp again, six months later…

After six months of leaving Fiasp on the shelf, and occasionally using it as an adjunct injection when fast carbs were consumed (where it still worked reasonably well), I thought it was time to go back and try to run my loop on it again. What would the outcome be?

Taking an empty insulin phial, I mixed up an F60H mix (60% Fiasp, 40% Humalog) and pulled it into the pump reservoir. A grand total of 5ml mixed up for seeing how going back to Fiasp after a six month lay up would fair. I had high hopes. As far as I could see, this was like starting for the first time once again. My body had had six months to recover and I should see the fast action straight away. Or so I hoped.

So what was the outcome? For six days I used this mix, and the overall results are shown below:

Comparing these this set of data with the previous week, there are a few things that stand out.

Whilst I’ve recently been less careful in my management of my diabetes, as the two AGP images show, both the data sets above show similar eating, and the second set of images is using Humalog.

What stands out is that the Time in Range with the Fiasp is a five percentage points lower than with the Humalog. What also stands out for me are the PGS score and Hba1C estimations. The PGS score is 50% higher using the Fiasp than the Humalog, and consequently, the predicted Hba1C is lower, as there are noticeably more hypos and the highs were higher than with Humalog. This is also reflected in the overall standard deviation, which is 37.1% of median on Fiasp and 29.8% of median on Humalog. Roughly 25% greater!

These numbers show that I was experiencing more variation with the F60H mix than I did with the Humalog and we all know that this isn’t desirable.

The second item of note is the differences between the two AGP graphs. The F60H week shows a marginally tighter fasted range, but once I started bolusing with it for food, that’s when the issues seem to occur. The thing that really stands out is the 10-90 spread late morning/early afternoon, which is the “brunch” period. I really struggled to avoid the F60H highs there, and ended up with additional insulin on board just to try and bring things back in line. Similar things happened late afternoon, but those are more consistent with Humalog.

The other reason for trying to use the F60H mix was to avoid adverse effects at the pump sites, and the first set seemed to be avoiding this. I took it off and there was no raised lump, and no pain from dosing. The second site, however, soon succumbed to the issues I’d seen in previous use of F60H. Within a day, there was the familiar “hot needle” pain, and on removal of the site (after two days), the red lump. That red lump is still not fully subsided, more than two weeks post removal.

I returned to Humalog after that.

So what do I conclude from this little experiment? I am still unable to use Fiasp in a mix with Humalog. The way my body reacted to it after my first 6-9 months of use has not gone away, and it didn’t take too much to get what I can only assume is some sort of immune response to reappear.

So it’s a case of “Body 2 – 0 Fiasp”. I’ll just have to wait for the next Faster Insulin to arrive…


    • I’ve tried Afrezza before. It works very well, however, it’t not available in the UK on prescription, or anywhere in Europe and importing it from the US is tremendously expensive, so trying to use it is very tough.

  1. Thank you for the post on Fiasp. I have followed your journey with great interest. I am MDI but also have issues with the volatile of Fiasp. Since your previous observations I decided to revert to Novorapid and only use Fiasp for corrections. Sometimes it works well, other times it’s like injecting water.
    I am now going to revert to Novorapid for corrections too to see if my control of highs is better or worse.

  2. I am about 4.5 months into Fiasp from Humalog, which I had used for 18 years. I had previously needed to prebolus at least 20 minutes in advance to prevent a spike, and find Fiasp acts substantially quicker (which is a huge QOL improvement). Unfortunately like you I am finding that with any significant carb lunch (more than 25g or so), I spike like crazy post-lunch. Fiasp keeps me in range extremely well when I have very few COB, but seems to work increasingly worse post-meal. And this is with OpenAPS helping out! Kind of at a crossroads, though I am going to try to adjust ratios and see what happens.

    Otherwise, I am not having any side effects re pain. Maybe slightly worse bruising at some sites, but nothing too bothersome. And I have not been mixing.

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