Riboflavin
Riboflavin is a tier 1 form of Riboflavin (Vitamin B2), used in 9,207 on-market products .
9,207
on-market products
tier 1
quality tier
n/a
elemental fraction
Why this tier: FMN is hydrolyzed to riboflavin by phosphatases in the upper gut before absorption (IOM 1998, ch. 5), undercutting claims that the phosphorylated form is inherently more bioavailable. Jusko & Levy 1967 studied absorption and excretion of riboflavin-5'-phosphate in man (PubMed has no abstract, so the specific equimolar urinary-recovery result is unverified).
Source: Institute of Medicine 1998, DRI for Thiamin, Riboflavin, Niacin, B6, Folate, B12, Pantothenic Acid, Biotin and Choline, ch. 5; Jusko WJ, Levy G. 1967, J Pharm Sci 56(1):58-62, PMID 6030496