Length of time Humalog takes to start working

Just a couple of facts to throw around, I’m on MDI, currently do not have a CGM, and I’m using Humalog and Lantus. I split my lantus dose, 10 units at night and 8 units in the morning. My lantus might be on it’s way out (12:00am I was at 144, by 1:20 am I was at 145, at 8:00am (no food in between I was at 180), so I’m switching to a new vial tonight, but regardless…

I started my routine with my lantus around 8:15am. Checked my sugar, was at 180- did my humalog dose (8 units for 36 carbs, plus 2 units for my correction) at 8:30am.

Decided to check my blood sugar before I started eating. I checked my sugar at 9:00, and I was still at 180. Waited another 10 minutes, checked (173), lost patience and started eating.

FTR I had a hard boiled egg, a small bowl of whole grain oatmeal, and 100g of apples.

I’m not really concerned about what happened after I ate, I’m more curious about what happened between the time I injected the insulin, and the elusive period of time it took for my blood sugar to go down.

I plan on repeating this tomorrow. Any suggestions? Maybe try taking my lantus earlier in the morning?

I do have a CGM and have learned (by “sugar surfing”) that it takes between 45-60 minutes for the Humalog to kick in at breakfast time. I was really surprised to learn this!

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I too have noticed that in the mornings it can take over an hour for the Humalog to have any effect on me at all.
I blame Dawn Phenomenon, of course.

I noticed that it takes longer for it to start working the higher my BG is when I wake up. If it’s over 120 it can take a good hour an half before I’ll see a tiny bit of a change. If it’s over 150 it can take even longer. I once woke up with over 250 and had to skip breakfast and basically not eat anything until almost 3 in the afternoon. The thing is, it has this weird delayed reaction so I won’t see much of a drop in BG after injecting and then hours later it will drop me to 40.

For me it generally takes 45min-1hr to see the “bend.” Shorter if my BG is around 100-120 to begin with, and stress levels can also have a huge impact. I’ve had work situations where I bolused and then so much stuff was coming at me that I never had a minute to break for lunch, and found the damn BG never did come down. Stress plays havoc with everything.

You can do this experiment yourself, even wihtout a CGM. On a morning with no deadlines, like the weekend, check your blood sugar, write it down, take your injection, then at 30 minutes post-injection check at 15 minute intevals and wait to eat until your glucose level shows a drop. It would be best if your blood sugar started at a somewhat normal level, like 90-140 mg/dl.

The advantage to doing the test is you will know how your body reacts, an advantage over what other people may report. Do the experiment more than once s you can discover the range that your body reacts to the onset of insulin action time.

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