Vitamin B2, also known as riboflavin, is generally taken without a definite dosing time. However, as some people taking it at night may cause insomnia and affect the absorption of trace elements, it is sometimes not recommended to take it at night.1. Causes insomnia: Vitamin B2 will participate in the metabolism of sugar, protein and fat in the body, which in turn will speed up the metabolism of the organism. This leads to prolonged excitement at night, followed by irritability and insomnia, so it is not recommended to take vitamin B2 at night. 2. Affecting the absorption of trace elements: Since all organs of the body maximize their role at night, some people taking vitamin B2 at night will affect the transformation of the organs into trace elements taken from food, thus affecting the absorption of trace elements. In addition, it is recommended to consult a doctor before taking vitamin B2 because overdosing may cause different degrees of discomfort. In particular, pregnant and lactating women, diabetic patients, and people with allergies should take it under medical advice.