I bought 500mg of vitamin b1 thiamine, is that too much?

DANGER: Replacing any of your b vitamins (especially in high dose) without ensuring an adequate intake of all your b vitamins can result in an overall deficiency of the ones not replaced. This is because the b vitamins often work in concert. Driving pathways that require b1 that also require b2/b3 can create a relative deficiency. Having too many members of the brass section can drown out the strings.