Generally speaking, I said you need to be cautious. Am I so off base here? OP did this under doctor's guidance, and thats the way to do it. Dont think its outlandish to be cautious when you go above and beyond RDA with anything. as per mount sinai, nyc: A daily dose of 50 to 100 mg is often taken as a supplement. Thiamine appears safe in these doses. But you should talk to your doctor before taking a large amount. aka, take caution when taking 2000 mg