I understood this to mean that my body only took what it needed and threw out anything beyond that. In reading this BB I have been learning more and more and went and bought myself a better brand of B-complex. I took it for the first time today - my urine has very little colour. Secondly, I see that Ester C comes highly recommended on this board. I have never heard that the color of your urine is an indication of how well it is absorbed.
Vitamin B makes urine yellow from the amount that is absorbed.
So far as I know this is true whether it is utilized inside the cell or not. I could benefit from someone helping me understand this better. Let us know what you learn. This thing about B-vitamins is rather odd. The man looked up Lithium, which apparantly is an element.