Why do multivitamin supplements make urine bright yellow?

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lisab
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I take a multi-vitamin supplement about 5 days a week. What is it in the pill that makes my urine turn bright, bright yellow? It looks almost fluorescent sometimes!
 

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lisab said:
I take a multi-vitamin supplement about 5 days a week. What is it in the pill that makes my urine turn bright, bright yellow? It looks almost fluorescent sometimes!

One of the B-vitamins...IIRC, it's the folate.
 
Does folate have a visible chromaphore? I always thought that color was due to the bright yellow riboflavin (B2).
 
pterins (folates as cryptochromes in leaves) have been shown to have max absorption at 380nm. It would give an orange-ish color I presume. Assuming folates in urine are similar.

http://mplant.oxfordjournals.org/cgi/content/full/1/1/68

However I always thought riboflavin was the major color culprit, too.
 
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When I take a pill high in iron, the excess iron turns my urine dark yellow or orange.
 
chemisttree said:
Does folate have a visible chromaphore? I always thought that color was due to the bright yellow riboflavin (B2).

Could be...I was certain on the B vitamin part, but since I've never seen any of the B vitamins individually, just as a complex, I could very well be wrong on which one it is that's the yellow culprit.

Edit: Yep, digging around, it is B-2. Even found an ancient archived thread here on it (but am not providing a link to it because it also contained some old crackpottery we wouldn't allow under current guidelines). My apologies for the misinformation about it being folate.
 
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