I'm 32 and have had a mild stutter my whole life. It seems like it has worsened in the last few years, or maybe just started bothering me more, so I sought out something to help. I read about Xanax had helped others and gave it a try. My doctor prescribed me .5 mg and I took that about twice a week for a year or so. It seemed to help a little, but it more just helped to take away the anticipatory anxiety about stuttering that I had, which seems to help to reduce my stuttering. After a while, it seemed like .5 mg was too much and seemed to adversely effect my stuttering so I switched to .25 mg and I now take that about every other day, sometimes only twice a week. I tried the thiamine and it might have helped, but I didn't feel a significant improvement, maybe I'll try it again.