To date, no well-established toxic effects from the consumption of excess thiamin in food or through long-term oral supplementation (up to 200 mg/day) are known (15, 20).

 

A small number of life threatening allergic reactions have been observed with large intravenous doses of thiamin (15).

 

Tolerable upper intake levels

Presently, a tolerable upper level (UL) of intake for vitamin B1 (thiamin) has not been defined.

 

Drug interactions

Please note:

Because of the potential for interactions, dietary supplements should not be taken with medication without first talking to an experienced healthcare provider.