Igf doesn't seem to effect my blood sugar. I train fasted as well ( just started this year to see if I liked it or not). First time I tried it on an empty stomach I just made sure that I had the glucose tablets that they sell at walmart on my person, so I felt hypoglycemia coming on I could get out of it real fast with the glucose tablets. I think they work almost instantly, maybe 5 minutes at the most.
Everyone is individual and you will have to do your own n=1 study!!