IM is the quickest also the area injecting is affected
How does the injection site affect absorption?
The abdomen is the fastest. Then comes arms, finally the thighs. Buttocks are up for grabs (sorry!). There are no scientific data on the rate of absorption in the buttocks. These differences may be used to prolong or speed up the effect of the injected insulin for special circumstances, but it's better to keep injecting within the same anatomical area all the time.
RADAR