Note: This document contains side effect information about riboflavin. Some dosage forms listed on this page may not apply to the brand name Vitamin B2.

Applies to riboflavin: oral capsule, oral tablet.

Serious side effects of Vitamin B2

Along with its needed effects, a dietary supplement may cause some unwanted effects. Riboflavin may cause urine to have a more yellow color than normal, especially if large doses are taken. This is to be expected and is no cause for alarm. Usually, however, riboflavin (the active ingredient contained in Vitamin B2) does not cause any side effects. Check with your health care professional if you notice any other unusual effects while you are using it.