Thiamin (thiamine) salts have been administered to man for months in daily doses up to 1 g or more without reported adverse effects, except hundred times the estimated intake of thiamin hydrochloride and thiamin monotrinate added to foods. Most cases of sensitiviity were induced by previous topical or parenteral exposure to thiamin.
Similarly, mice and rats fed daily for three generations with several hundred times their normal requirements of thiamin showed no adverse effects.
Absorption of orally administered thiamin is regulated by a transport mechanism which offers an effective protection against overdosage. Excess thiamin in the tissues is rapidly excreted in the urine.
In view of the above considerations, the Select Committee concludes that:
There is no evidence in the available information on thiamin hydrochloride or thiamin mononitrate that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when it is used at levels that are now current or that might reasonably be expected in the future.