Hi, i do not take any supplements or medications. Dont even know if there's medications for stuttering. Yes, anxiety and stress play a big role, while kot causing the stuttering, can be a booster for it. Take while in bed or watching your favourite show, you can try to repeat certain phrases they say which you know you'll stutter on a normal day you would have more chances of success but repeat the same movie but with atleast 2 people present and having different conversations less chances (self made experiment)