I've taken thiamine+ magnesium glycinate for over a year. And I thought it was working for me. Now I believe it's all just a mind game. Looking back at the time I used to supplement with these two, I think I just used to mask the bad moments and highlight only good moments so as to prove this supplement worked. Only when I started to investigate with unbiased view, I started to see these supplements didn't really do much. Of course taking a multivitamin and b complex is good for you provided you've deficiencies of those said vitamins/minerals, otherwise I'd say it's a waste of money. Go for speech therapy, get good sleep, exercise, maybe take a multivitamin (if you have deficiencies), practice infront of mirror, sing a song daily. I have found that these things help better than any supplements, for free too.