Taking a vitamin B complex daily as a vegan can be beneficial to ensure adequate intake of essential B vitamins, particularly vitamin B12, which is harder to obtain from a vegan diet¹². Since vitamins B12 and other B vitamins are water-soluble, the body typically expels excess amounts through urine, reducing the risk of overdose from dietary sources or supplements³.

However, while a daily intake might be beneficial, particularly for those feeling better on supplement days, it's important not to exceed the recommended daily allowance significantly unless advised by a healthcare professional. Excessive intake over long periods may sometimes have potential side effects, although the risk for B vitamins, particularly B12, is generally low since the body expels excess amounts⁴.

Ultimately, deciding to take it daily versus three times a week can depend on how you feel and your specific dietary needs. If you are experiencing noticeable benefits taking it daily, and if the dosage aligns with your body's needs without causing adverse effects, it could be reasonable to continue daily use. It might still be helpful to consult with a healthcare provider or a nutritionist, especially with the usual concept of varying individual needs¹⁴.