I often have 2 different types of site failures. One is where the insulin basically doesn’t absorb at all, and simply pools up under the skin. When removing the site, insulin will flow out fairly readily, or you can squeeze it out. That is pretty straight forward as to why BG would not be coming down. The other is when it seems to absorb into the skin, but apparently doesn’t absorb into the bloodstream, or if it is absorbing it does it over a long period of time. In these circumstances I can take 2-3 times as much insulin as required, but my BG doesn’t budge much at all. It is like the insulin just isn’t working. It will remain flat, but high, or slowly continue creeping up. The insulin is definitely not leaking out, and when I take the site out there will sometimes be a couple units of insulin that weren’t absorbed all the way, but clearly most of it was absorbed somewhere.
The only thing that seems to make sense is that it degrades once in the body and when it finally is diffused out into the bloodstream it has degraded to the point of not being effective anymore or something.