Nope, although Paul Stamets claims he has been cured for most of the part. But in this video (https://www.youtube.com/watch?v=3h39ax9iu6o) which was recently posted here too, he said that he still stutters in loud environment, like in bars. So, he is not completely cured, but it’s obviously much better than it was before for him. I think it’s almost impossible, as lot of people said here, stuttering has its origin in some neurological defect in the human brain. Unfortunately, I don't think that taking psychedelics will repair that. In my experience (i have tried a lot of psychedelics - lsd, dmt, 5-meo-dmt, ...), it didn't do anything with my stuttering and still stutter, sometimes quite substantially. It's strange but for example on acid, it is much harder to talk for me. But anyway, you can try, psychedelics have other benefits.