Riboflavin (Vitamin B2) supplements help some people with certain genetic polymorphisms.

Riboflavin (Vitamin B2) is a water-soluble vitamin that is a cofactor for many enzymes in the body.  To put it in simpler terms: riboflavin is vitally important!

Riboflavin is a ribose sugar bound to a flavin molecule.  It is the precursor to FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide), which are coenzymes involved in numerous vital functions in our bodies.  FAD is part of the Kreb’s cycle, producing energy in the mitochondria.  FAD is also involved in detoxification as a cofactor for some CYP450 enzymes as well as for glutathione recycling.[ref]

Riboflavin is found in dairy products, eggs, liver, enriched flour, and in minor amounts in many foods.  The US RDA is 1.6mg for adults, and most populations are estimated to meet this with their daily food consumption.  Dietary insufficiency can cause angular cheilitis (cracks at the corners of the mouth), anemia, burning mouth, sore throat, and vision issues.  [ref]


There are several genetic variants that can cause an increased need for riboflavin.


rs1801133 (C677T)   This fairly common variant causes a change in the shape of the MTHFR (methylenetetrahydrofolate reductase) protein that decreases its ability to bind to FAD.  [ref]

  • Riboflavin supplement lowered homocysteine levels in those with the AA genotype.  [ref][ref]
  • For those with the AA genotype and high blood pressure, riboflavin (1.6 mg/day) lowered systolic blood pressure by 5 – 13 mmHg.  [ref]

Gene: FMO3
FMO3 (flavin-containing monooxygenase 3) variants can cause a decrease in the FMO3 enzyme, which breaks down certain nitrogen-containing amines and some sulfur-containing compounds. FMO3 is the primary way that the body breaks down trimethylamine. Decreased FMO3 activity can cause an increase in trimethylamine, which causes a fishy smelling body odor.[ref]  Some people with mild FMO3 variants are helped with riboflavin.[ref]

rs1736557 (A is the risk allele)

  • This is listed as possibly a contributor to trimethylaminuria. [ref]  It is listed in ClinVar as both benign and pathogenic, so it may not be a problem for most people unless coupled with other variants.

rs2266782 (A is the risk allele)

  • reduced enzyme activity [ref]

rs909530 (Tis the risk allele, N285N)

  • reduced enzyme activity [ref]

rs2266780 (G is the risk allele, E308G)

  • reduced enzyme activity [ref]

rs61753344 (T is the risk allele)

  • causes varying degrees of trimethylaminuria [ref]


Part of the electron transport chain, problems with the ETFDH gene can cause MADD (multiple acyl-CoA dehydrogenase deficiency).  These are fairly rare mutations.

Gene: SLC52A3 (Riboflavin transporter, also known as C20Orf54)

i5008314  (rs267606684, A)

  • Pathogenic for Brown-Vialetto-Van Laere, a rare neurological condition which is often normalized by high dose riboflavin.  [ref]

Gene: DLD (Dihydrolipoamide dehydrogenase) [ref]

i5003700 (T)

  • Dihydrolipoamide Dehydrogenase Deficiency

Gene: SLC25A32 (encodes the mitochondrial FAD transporter)

rs147014855 (T)

  • T allele is listed in ClinVar as pathogenic for exercise intolerance that is responsive to riboflavin. [ref] [ref]

Diet and Supplements:

Additional Reading:


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