Great question! When we take water soluble B-vitamins they will be excreted after use. B2 (riboflavin) can cause urine to turn bright yellow, but this does not mean it is being wasted. Water soluble vitamins are used by the body for myriad metabolic processes, and are naturally excreted after use, which is what we want. B-12 is the only B vitamin stored by the body, the rest are excreted via elimination of the bowels and bladder. – Coach Zoe