No toxic or adverse effects of high vitamin B2 (riboflavin) intake in humans are known.

 

High-dose riboflavin has been found to intensify urine color to a bright yellow as a harmless side effect.

 

In vitro (cell culture) studies indicate that excess riboflavin may increase the risk of DNA strand breaks in the presence of chromium, a known carcinogen (23). This may be of concern to workers exposed to chrome, but no data in humans are available.

 

Tolerable upper intake levels

Presently, no tolerable upper level of intake (UL) has been established for vitamin B2 (1, 24).

 

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.