I tried it for about 5 weeks. I thought I was seeing improvement while taking it, but when I stopped to see what would happen I didn’t experience any worsening in my stutter. Honestly I think that me thinking that the vitamin made me improve wasnt true, my improvement came from a reduction in my anxiety in me practicing my speech. Vitamin B1 is worth a try. But don’t go into it expecting specific results. You will likely be let down if you expect a cure