I have thought quite a bit about this and have taken some substances before that I can't mention here or I'll get in trouble that have completely let me be stutter free while on them. I tried to really focus on what I was doing different with my muscles, my brain, etc...because I was fluent as hell, could talk as fast as that Twista guy. After it wore off though, it was back to stuttering as normal and no matter how much I tried to remember what I was doing to specifically not stutter, it didn't work. But I think it's in our heads, like a chemical imbalance of sorts. If I'm on a drug that temporarily alters brain chemistry which makes my stutter go away then I am surprised as well there isn't a pill or something for it. The last thing I want to do though is take more pills. I went to a speech therapist as a kid and they had me read a paragraph out of a book as slowly as I possibly could. I did this routinely until I started talking slower without realizing it. Speaking slowly and with a calm voice does help a lot.