Another water-soluble vitamin of the B complex, riboflavin acts as the coenzymes flavin mononeucleotide (FMN) and flavin dinucleotide (FDN) to convert sugars, proteins and fats into energy. It is indispensable for red blood cell formation and the production of antibodies. It eases eye fatigue, helps prevent migraines, and it is useful in acne rosacea and carpal tunnel syndrome. In combination with vitamin A, it helps maintain the internal mucous membranes of the respiration, circulation, digestion and elimination channels, while in combination with vitamin B6 it converts tryptophan to nicotinic acid.

Best food sources are yeast extract, brewer's yeast, liver, wheat germ, eggs, wheat bran, cheese, meats, soya, yogurt, milk, pulses and green vegetables.


  • Eye soreness and ulceration
  • Gastric and duodenal ulcers
  • Mouth sores
  • See above under Functions


  • Bloodshot eyes and "grit" under the eyelids
  • Cracks and sores at mouth corners
  • Dizziness, insomnia, trembling
  • Fatigued and sensitive eyes
  • Inflamed tongue and lips
  • Scaling of face skin

Riboflavin is generally such a safe vitamin that it is used as a food additive and colorant. It may give urine a strong yellow color, but this is harmless. However, in case of kidney disorders or cataracts, consult with a qualified and experienced health care professional. Cancer patients should know that riboflavin deficiency inhibits growth of cancerous tumors; before taking a supplement, consult with a cancer specialist. Certain drugs, such as the antibiotics erythromycin, streptomycin and tetracycline, central nervous system drugs like amitriptyline, chlorpromazine and imipramine, probenecid and related preparations for gout, many diuretics, and oral contraceptives, negatively affect the body's absorption of riboflavin. Therefore, take riboflavin supplements at different times. Riboflavin deficiency may cause congenital malformations including cleft palate.