Taking a Vitamin B complex can be beneficial, especially if you're a vegan, since B vitamins such as B12 might be lacking in a plant-based diet¹. However, there are considerations regarding the daily intake and the safety of certain vitamins at high doses.

1. Safety of Vitamin B Complex: Generally, most B vitamins, including B12, are water-soluble, meaning the body usually excretes any excess through urine, which minimizes concerns about toxicity at typical doses². However, there are exceptions:

   • Vitamin B6: High doses (exceeding 100 mg per day) over prolonged periods can cause nerve damage and other health issues³. It's unlikely that a typical B complex supplement contains such high amounts, but it's worth checking.
   • Niacin (Vitamin B3): High doses without medical supervision could lead to liver issues¹.

2. B12 and Vegan Diets: Since vitamin B12 is crucial for nerve health and the production of DNA and red blood cells, ensuring an adequate intake through supplements is important for vegans¹. There's minimal risk with taking higher doses of B12 daily as the body will excrete the excess¹.

3. Sensation of Well-being: The sensation of feeling better on days when you take the supplement may be related to improved energy metabolism or other subtle changes in physiological function. This is subjective and can vary among individuals².

4. Recommended Approach: It’s generally safe to take a daily Vitamin B complex, especially if the doses do not exceed the upper intake levels set for vitamins like B6 and B3. However, you should consult with a healthcare provider to tailor supplement use to your specific dietary needs and health goals².

Ultimately, whether you take it three times a week or daily might depend on the specific formulation of your supplement and your personal health goals, but daily use is generally safe for most populations within the recommended limits.