Sorry but I really think this is placebo. So here’s the thing: I had a period of my life where I was very down to the verge of ending it. Impressively, I find I stopped stuttering during that time. Once I stopped giving a fuck, I stopped stuttering. Later my mental health improved and the stuttering came back, but was significantly less severe. This have really lead me to think that stuttering is a mental issue. Yes I know there are studies showing people who stuttering have different brain imaging and whatever. Guess what, anxiety does that to your brain too.