I live in Sudan and we dont have pure Thiamin HCl tablets only, we have a multivitamin B complex. I take 10 tablets each day. Yes its a alot and the impact on my wallet is also pretty significant but its worth it for me to live a relatively nornal life. There are no side effects associated with high dose Thiamin.. however make sure that you are not taking too much B6 ( if youre using a B complex tablet like me) as B6 Megavitaminosis has significant side effects.