Interesting. I've had relapses, but unlike before I started taking the vitamin, the relapses generally disappear within two days. The higher my dose, the better my speech is. However, it's clear this vitamin trick only works for certain stutterers. Many stutterers have reported no improvement after weeks of supplementation. For those lurking here: If you experience even a mild improvement on vitamin B1, I strongly encourage you to up to your dose and see if it works for you. Since vitamin B1 is a water soluble vitamin, increasing the dose will not hurt you.