Does taking a b-complex vitamin and having bright yellow urine mean you are taking enough?

Enough B1 and B2: Vitamins B1 and esp. B2 have a yellow color so bright yellow urine suggests enough B1 and B2. But B3, 5, 6, 12 and folate aren't yellow and you might still have inadequate levels of those. Many have difficulty absorbing B12. Nearly half of people have trouble metabolizing folic acid and need the L-5-MTHF form of folate. Fasting blood homocysteine can indicate if you have enough B6, B12 and folate.