[TinyRick]

Does anyone know if this enzyme is present in B vitamins or produced by the gut biome due to excessive intake of B vitamins (B-2 and B-12 specifically)? In my experience, an excess of B vitamins causes the urine to turn yellow (independent of hydration level) and was curious if this enzyme plays into that at all.

[FreeFull]

Vitamin B2 (Riboflavin) is yellow, and when you consume it, the excess ends up going into your urine, making it more yellow (and fluorescent).

[notamy]

Riboflavin (B2) is a bright yellow and fluorescent under UV light. B12 is red and aiui it takes a LOT of B12 to turn urine red. This happens because both are water-soluble.