I too have been using Fiasp for a couple of years due to Novo(not so)Rapid.
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@helli I had a period of frustration (3 months) before I found out how to make it work for me.
It is faster than NR but still not as fast as I would like and I usually need 45 mins prebolus time at breakfast and 20 mins at other times of day as oppose to 75mins and 30mins with NR.
Like helli I find that its speed of activity depends on my BG but even if my levels are in the 4s and 5s I need about 30mins prebolus time at breakfast. Again, like helli, when levels are above 10 it acts like water but I find that I actually need to "rage bolus" or more often stack smaller corrections to shift it and it can take several hours to bring me down into range.
It is very responsive to exercise and I have to be quite careful about exercising whilst a bolus is still active.
One of the good things I find is that it's activity is quite short, so I don't generally get any nasty surprises 4 or 5 hours after a bolus. It is usually done by 3 hours for me.
I personally haven't noticed it lose it's potency but I currently go through a cartridge every 10 days, so it probably doesn't get a chance. I definitely need to use more Fiasp than I did NR and I think that was one of the problems I had with adjusting to it. Once I became a bit more "gung ho" with it, I managed better, but without Libre I don't think I would have been comfortable having that heavy handed approach and in fact, it was the sheer frustration that lead me to become more heavy handed ad make the breakthrough.... I had 2 trials of Fiasp and gave up 3 months into the first one but promised myself I would stick at it for a full year the second time....Had another 3 months of frustration and then cracked it.... Clearly I am a slow learner
🙄 Being proactive and keeping levels below 10 as much as possible helps enormously because once I go above 10 I have to really get heavy handed to get levels down again.
Do I think Fiasp is better than NR?... Probably, slightly..... and I would almost certainly find it very frustrating to go back to NR, but I don't love Fiasp like I love my Levemir. I have considered trying other faster insulins like Lyumjev but I have a sneaky feeling that it is my body which is sluggish in absorbing and responding to bolus insulin rather than the insulin itself and having talked it over with my consultant he is of the same opinion that I would not gain from trying another one, so I am now settled on Fiasp and I make it work well for me now, partly by being a bit heavy handed with it, but I didn't find it easy or a straightforward swap. I do however now have a workable routine with it and my stats are really good with a TIR of 95% for the last 14 days, although that is certainly aided by now having Libre 2 with alarms.
Sorry if that doesn't paint a very positive picture of Fiasp. Hopefully you can learn from my own and helli's difficulties to establish a working relationship with it more quickly.
