Urine Excretion

As per the Institute of Medicine, “Normally, the major excretory product is 4-PA, which accounts for about half the B₆ compounds in urine (Shultz and Leklem, 1981). Other forms of the vitamin are also found in urine. With large doses of B₆, the proportion of the other forms of the vitamin increases. At very high doses of PN, much of the dose is excreted unchanged in the urine.”  …. 

Read more: Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B₆, Folate, Vitamin B₁₂, Pantothenic Acid, Biotin, and Choline.