Skip to main content




Ingredient Type: Extract, Constituent, Concentrate, Metabolite

Also Known As: Bioflavonoid complex, Bioflavones

Bioflavonoids are biologically active members of the group of plant-derived compounds known as flavonoids.  They were first discovered in 1936 by Nobel-prize winning scientist, Albert Szent-Gyorgi, who originally named them “Vitamin P.”  Since then, over 4,000 flavonoids have been identified and classified according to chemical structure (5).  Bioflavonoids have antioxidant properties thought to be particularly beneficial for capillary strength.  Bioflavonoids from citrus fruits are believed to work with vitamin C to promote immune system health (1).

Bioflavonoid supplements are available as individual flavonoids, such as quercetin (derived from onions), and as multiple bioflavonoid complexes (e.g. derived from citrus fruits) that are often combined with vitamin C.  Compounds commonly featured in citrus bioflavonoid supplements include hesperidin, rutin, naringin, and quercetin.  These phytonutrients are thought to be vital for proper absorption of Vitamin C (2).

Hesperidin is found most abundantly in the peel and membranous parts of lemons and oranges.  Hesperidin is often used for the treatment of varicose veins and hemorrhoids.  A deficiency of hesperidin in the diet has been linked with abnormal capillary function, extremity pain and leg cramps (3).

Rutin and quercetin are the strongest bioflavonoid anti-oxidants.  As such, these 2 bioflavonoids have very powerful anti-inflammatory benefits.  They seem to have their greatest effects on the bloodstream and capillary beds, and have also been shown to be highly effective at preventing and treating varicose veins.  Rutin and quercetin are found in large quantities in the fruits and rinds of lemons, limes, grapefruits, & oranges (4).


Citrus Bioflavonoids are typically used in health supplements to support the immune system (6).

Bioflavonoids are used as an aid to enhance the action of vitamin C, to support blood circulation, as antioxidants, and to treat allergies, viruses, or arthritis and other inflammatory conditions (7).


A 1955 study by Dr. Biskind looked at 69 cases of acute respiratory infections that were treated with a whole water soluble citrus bioflavonoid complex.  The disorders included the common cold, acute follicular tonsillitis, & influenza.  Within 8 to 48 hours all but 3 cases saw a significant decline in infection.  Dr. Biskind credited this rapid recovery to improved capillary permeability and the enhanced vitamin C bioavailability (8).

In 1962, Dr. Robert Cragin used lemon-orange derived bioflavonoids on different groups of athletes in a double-blind study.  It was found that the athletes taking bioflavonoids experienced less muscle and joint injuries than the control group.  These athletes also recovered quicker from similar injuries than the group of athletes not taking the bioflavonoids.  The addition of vitamin C to the bioflavonoids (as seen in citrus fruits) appeared to enhance these effects (9).

Studies have shown benefits of the citrus bioflavonoids on capillary permeability and blood flow.  This is likely due to the powerful anti-inflammatory effects of these phytonutrients.  This is especially important for oxygenating tissues and maintaining normal blood pressure.  They also reduce swelling, venous backup, and edema.  This process frequently improves respiration in the lungs (10).


Citrus bioflavonoids appear to have very low toxicity and to be safe at the typical dosage range (250-500mg/day) (11).

There are no known restrictions on food, beverages, or activities while someone is taking bioflavonoids unless otherwise directed by their healthcare provider (11).

Research indicates that some flavonoids found in grapefruit juice may interfere with an enzyme that breaks down certain drugs, increasing the drugs’ activity (11).


  1. Antioxidant Capacity, Anticancer Ability and Flavonoids Composition of 35 Citrus (Citrus reticulata Blanco) Varieties. Wang Y, Qian J, Cao J, Wang D, Liu C, Yang R, Li X, Sun C. Molecules. 2017 Jul 5;22(7). pii: E1114. doi: 10.3390/molecules22071114.
  2. Anti-Inflammatory and Neuroprotective Constituents from the Peels of Citrus grandis. Kuo PC, Liao YR, Hung HY, Chuang CW, Hwang TL, Huang SC, Shiao YJ, Kuo DH, Wu TS. Molecules. 2017 Jun 9;22(6). pii: E967. doi: 10.3390/molecules22060967.
  3. Investigation of the interaction for three Citrus flavonoids and α-amylase by surface plasmon resonance. Liu X, Luo F, Li P, She Y, Gao W. Food Res Int. 2017 Jul;97:1-6. doi: 10.1016/j.foodres.2017.03.023. Epub 2017 Mar 12.
  4. Nutraceutical Value of Citrus Flavanones and Their Implications in Cardiovascular Disease. Testai L, Calderone V. Nutrients. 2017 May 16;9(5). pii: E502. doi: 10.3390/nu9050502. Review.
  5. Neuroprotective Effects of Citrus Fruit-Derived Flavonoids, Nobiletin and Tangeretin in Alzheimer’s and Parkinson’s Disease. Braidy N, Behzad S, Habtemariam S, Ahmed T, Daglia M, Nabavi SM, Sobarzo-Sanchez E, Nabavi SF. CNS Neurol Disord Drug Targets. 2017;16(4):387-397. doi: 10.2174/1871527316666170328113309.
  6. Bioavailable Citrus sinensis Extract: Polyphenolic Composition and Biological Activity. Pepe G, Pagano F, Adesso S, Sommella E, Ostacolo C, Manfra M, Chieppa M, Sala M, Russo M, Marzocco S, Campiglia P. Molecules. 2017 Apr 15;22(4). pii: E623. doi: 10.3390/molecules22040623.
  7. C-Glycosyltransferases catalyzing the formation of di-C-glucosyl flavonoids in citrus plants. Ito T, Fujimoto S, Suito F, Shimosaka M, Taguchi G. Plant J. 2017 Jul;91(2):187-198. doi: 10.1111/tpj.13555. Epub 2017 Jun 5.
  8. The Citrus Flavanone Naringenin Produces Cardioprotective Effects in Hearts from 1 Year Old Rat, through Activation of mitoBK Channels. Testai L, Da Pozzo E, Piano I, Pistelli L, Gargini C, Breschi MC, Braca A, Martini C, Martelli A, Calderone V. Front Pharmacol. 2017 Feb 27;8:71. doi: 10.3389/fphar.2017.00071. eCollection 2017.
  9. The effects of flavanone-rich citrus juice on cognitive function and cerebral blood flow: an acute, randomised, placebo-controlled cross-over trial in healthy, young adults. Lamport DJ, Pal D, Macready AL, Barbosa-Boucas S, Fletcher JM, Williams CM, Spencer JP, Butler LT. Br J Nutr. 2016 Dec;116(12):2160-2168. doi: 10.1017/S000711451600430X. Epub 2017 Jan 16.
  10. Bioactive compounds in foods: their role in the prevention of cardiovascular disease and cancer. Kris-Etherton PM, Hecker KD, Bonanome A, Coval SM, Binkoski AE, Hilpert KF, Griel AE, Etherton TD. Am J Med. 2002 Dec 30;113 Suppl 9B:71S-88S. Review.
  11. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Anand David AV, Arulmoli R, Parasuraman S. Pharmacogn Rev. 2016 Jul-Dec;10(20):84-89. doi: 10.4103/0973-7847.194044. Review.
  12. Protective effect of flavonoids against red blood cell hemolysis by free radicals. Asgary S, Naderi G, Askari N. Exp Clin Cardiol. 2005 Summer;10(2):88-90.
  13. Health effects of quercetin: from antioxidant to nutraceutical. Boots AW, Haenen GR, Bast A. Eur J Pharmacol. 2008 May 13;585(2-3):325-37. doi: 10.1016/j.ejphar.2008.03.008. Epub 2008 Mar 18. Review.
  14. Cardiovascular Disease: A Target for the Pharmacological Effects of Quercetin. Gormaz JG, Quintremil S, Rodrigo R. Curr Top Med Chem. 2015;15(17):1735-42. Review.

See the entry for bioflavonoids, the entry for bioflavonoids, the Michigan Medicine Health Library entry for flavonoids, or this Rose Medical Center article on citrus bioflavonoids for more information.