Riboflavin (B2)
The bright yellow vitamin that makes your urine neon. Riboflavin is converted to FAD and FMN - cofactors required by over 100 enzymes including MTHFR, glutathione reductase, and the entire electron transport chain. It's the unsung hero of methylation and energy.
Key Functions
MTHFR Support
FAD is the cofactor for MTHFR enzyme. Low B2 can worsen MTHFR C677T effects on methylation.
Glutathione Recycling
Glutathione reductase requires FAD to regenerate reduced glutathione from oxidized form.
Energy Production
FAD and FMN are electron carriers in mitochondria. Essential for Complex I and II function.
B6 Activation
Pyridoxine (B6) requires FAD-dependent oxidase to become its active coenzyme form (PLP).
Iron Metabolism
Needed for iron absorption and mobilization from storage. Deficiency can cause anemia-like symptoms.
Neurotransmitter Metabolism
MAO (monoamine oxidase) is FAD-dependent. Involved in dopamine, serotonin, and histamine breakdown.
The MTHFR-Riboflavin Connection
Riboflavin may be the most overlooked support for MTHFR variants:
C677T Variant
This common variant reduces FAD binding affinity. More riboflavin can help compensate by driving more FAD into the enzyme.
Blood Pressure
Studies show riboflavin (1.6mg/day) can lower blood pressure specifically in people with MTHFR C677T.
Homocysteine
Adequate B2 helps MTHFR produce methylfolate, which is needed to recycle homocysteine.
Before Methylfolate
Consider optimizing B2 status before supplementing methylfolate, especially with MTHFR variants.
Deficiency Signs
Riboflavin deficiency (ariboflavinosis) often co-occurs with other B vitamin deficiencies:
Mouth/Lips
Angular cheilitis (cracked corners of mouth), sore throat, magenta tongue.
Eyes
Light sensitivity, burning, itching, bloodshot eyes. Cataracts with chronic deficiency.
Skin
Seborrheic dermatitis, especially around nose and ears. Dry, scaly skin.
Food Sources
Riboflavin is found in many foods but is easily destroyed by light (store milk in opaque containers):
Best Sources
Liver, eggs, dairy, almonds, mushrooms, beef, nutritional yeast.
Good Sources
Spinach, salmon, pork, fortified cereals, tempeh.
Supplementation
10-50mg for general support. R5P (riboflavin-5-phosphate) is the active form for those with absorption issues.