I've had a friend (illegally) give me his xanax before for interviews and it was EXTREMELY effective at reducing my stutter. I aced the interview and I felt like my speech was flawless during the entirety of it! With that being said though, xanax (and presumably other benzos) isn't a solution to treating a stutter or even anxiety. There are way too many side-effects to it and it's extremely addictive. It's also something that you can't really do often because of its reduced effectiveness over long term periods. Might be good for a one-time thing, but I've found that therapy (both speech therapy and cognitive behavioral therapy) to have more effect on improving my life as a whole, than what any drug could do. As for the blood flow part, I haven't heard of that but I'll definitely be checking that out.