Timing of a superbolus

If I don’t start eating within about 15 minutes of a pre-bolus, I’m apt to plunge, so I’m a little worried about the extra insulin of a superbolus. Those of you who regularly superbolus, do you find you need to shorten or eliminate your pre-bolus time?

For me, a superbolus does not affect the amount of pre-bolus time. If my starting blood glucose, however, is less than 85 mg/dL (4.7) then the pre-bolus time may be shortened and I need to keep a close eye on my CGM.

It’s my understanding, in general, that the relative size of the insulin dose will affect that dose’s duration but not its onset. Your diabetes may vary, of course. Maybe you should do a personal experiment, or three. :wink: Keep a log and emergency glucose nearby.

When I was using NovoRapid I super bolused for almost every meal. I found I still needed to pre-bolus, but if my blood sugar was under 6 I had to eat within about 10-15 minutes max just like you are saying or would drop fast. When I switched to Fiasp I would have to eat almost right away when I superbolused to avoid this, but found pre-bolusing 15-20 min on Fiasp works the same as using NovoRapid with a superbolus, and was having highs later from superbolusing since the tail is shorter, so I don’t do it anymore.

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Pre-bolusing on NovoRapid without the superbolus would take 30-40 minutes to drop me though, so for you maybe no pre-bolus is necessary or 5 minutes at most.

Terry, are you saying you do a superbolus even if you’re < 85? I thought it was only for when you were out of range high and still wanted to eat a meal.

maybe I just don’t have the superbolus calculations firmly in my craw

I should use past tense here as I’m currently using a variation of the super-bolus with the Loop system. I wouldn’t typically use a super-bolus when my blood sugar is at the low end of normal, but would if I thought the post-meal food/insulin contest favored the food. If my pre-meal glucose was at the high end of normal, I would increase the pre-bolus time and use a super-bolus.

Caleb used to super bolus for breakfast every day. He would still pre bolus for about 10 minutes, however we really had to be careful that he did not get distracted and delay eating any more than that. I think Terry’s point about the onset not changing contingent upon the size of the bolus is valid. The risk associated with not timing things right is much greater with a bigger bolus though. Caleb is not a low carber. The reason we superbolused for breakfast and only breakfast was bc of his lack of active insulin overnight (different for other meals bc there’s some tail of insulin from previous meals to help) and just general insulin resistance after being inactive all night. We couldn’t otherwise avoid the spike, and he didn’t need more insulin for the meal - just needed it to be timed differently. Breakfast is his biggest meal bolus of the day with his most aggressive IC ratio, so the amount of insulin is great, and we can’t mess with the timing at all.

This is definitely a useful application, but not the only one. Super bolus is useful in any situation where you want to front load the insulin delivery to avoid a spike. It’s useful for high glycemic meals - you probably wouldn’t want to do it for lentil soup.

This is the strategy used in current DIY hybrid closed loops - increasing basal when bgs start to rise and decreasing basal when they start to fall - all with the intention of flattening out the bg line by micromanaging the timing of the delivery of insulin.

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