How do you feel something on Kratom?

I have been experimenting with kratom and tried a low dose. I experienced the stimulation effects of that dose.
I then tried an 8 gram dose and did not feel any sort of sedation that is talked about. It’s worth mentioning that I did take it after eating, which might have blunted it? I ended up having my stomach hurt for a bit but that was it.
I was only able to feel it when I smoked another time. I tried it at a 4 gram dose, but I don’t want to have to smoke in order to get the effects. I also experienced this when trying 20mg of oxy. I felt something for maybe 30 min and then it went away. Do I need to do higher dose or am I just a non-responder to opiates?