Riboflavin
Riboflavin is a tier 1 form of Riboflavin (Vitamin B2), used in 8,626 on-market products .
8,626
on-market products
tier 1
quality tier
n/a
elemental fraction
Why this tier: A classic PK study found equimolar oral doses of riboflavin and riboflavin-5'-phosphate produce the same urinary riboflavin recovery -- FMN is dephosphorylated to riboflavin before/during absorption, undercutting claims that the phosphorylated form is inherently more bioavailable.
Source: Jusko WJ, Levy G. 1967, J Pharm Sci, PMID 6030496