grapefruit seed extract

What Is It?
Health Benefits

Dosage Information

Guidelines for Use

General Interaction

Possible Side Effects



Evidence Based Rating Scale

What Is It?

This unlikely herbal infection-fighter is synthesized from the seeds and pulp of the grapefruit. The properties of grapefruit seed extract (GFSE) were discovered in 1973 by Dr. Jacob Harich who was studying natural substances capable of eliminating microorganisms without harming humans. (1)Today, farmers in Europe use a powdered form of GFSE in fish and poultry feed to prevent infections caused by Salmonella and E. Coli. Cosmetic companies add it to their products as a preservative due to its antimicrobial effect. (2) GFSE is sometimes called citrus seed extract and many other names. Sometimes labeled as GSE, it should not be confused with Grape Seed Extract.

Health Benefits

Grapefruit seed extract has been most heavily promoted as a treatment for Candida albicans, a form of yeast that occurs naturally in the human body and that can cause symptoms when it grows out of control. GFSE is particularly popular for controlling vaginal yeast infections caused by Candida and for treating a poorly understood intestinal condition called Candida overgrowth syndrome (COS).

Some nutritionally oriented doctors recommend GFSE capsules, liquids, and powders for bacterial, viral, and fungal infections, including COS. One laboratory study indicated that GFSE has antimicrobial properties against a wide range of organisms at dilutions found to be safe for humans. (3)

GFSE may benefit gastric lesions caused by stress or ethanol. In one animal study, rats were treated with GFSE thirty minutes prior to being subjected to ethanol or another stressor. The number and area of gastric lesions that formed were measured and compared to those in rats that did not receive GFSE. Lesion number and size were reduced by as much as 50% in the group receiving GFSE depending upon the dosage. (4)

The antioxidant properties of GFSE may benefit pancreatitis (inflammation of the pancreas) caused by ischemia/reperfusion—an experimental model of tissue damage in which blood flow and oxygen to an area are restricted (ischemia) and then allowed to return (reperfusion). In one animal study, GFSE supplements taken before an ischemia/reperfusion challenge exerted protective activity against pancreatitis. (5)

Specifically, GFSE may help to:

Control growth of Candida albicans. Candida albicans is the fungus present in most vaginal yeast infections. In one animal study evaluating the effect of an antifungal drug, mice infected with Candida were randomly assigned to receive either the antifungal drug or placebo.  The same mice were randomly assigned to receive either water or grapefruit juice as drinking fluid. In the Placebo drug group, mice given grapefruit juice to drink survived longer than those drinking water. (6) Additionally, a laboratory study found that a 33% grapefruit extract showed potent antifungal activity against Candida albicans that was isolated from patients with symptoms of candidiasis, or yeast infection. (7) One source notes that GFSE alone is not sufficient to cure vaginal yeast infections, but it is effective in combination with dietary modification. Some fruits and many foods that contain sugar promote the growth of yeast: their elimination along with GFSE may help to reduce infections. (8)

Slow the development of colon cancer. One animal study suggested the components of grapefruit seed and pulp may help suppress the development of colon cancer. Studies are needed to determine GFSE's effect in human colon cancer. (9)

Relieve symptoms of diabetes. In one animal study, diabetic rats were given 100-600 milligrams/kilogram of GFSE or placebo each day for 30 days. At the end of the study, the rats that were given GFSE showed significant reductions in blood glucose levels, triglycerides, LDL ("bad") cholesterol, and total cholesterol; and an increase in HDL ("good") cholesterol. (10) Studies are needed to determine if GFSE has the same effect in humans.


  • capsule
  • creams
  • liquid
  • powder

Dosage Information

Special tip:

Given its bitter taste, the liquid extract is often mixed with a sweet fruit juice to make it more palatable.

  • For vaginal yeast infections: When purchasing a GFSE douche, follow package instructions.

  • For Candida overgrowth syndrome: the usual starting dose is 10 drops taken twice daily with water or fruit juice between meals for the first three days. This is followed by 15 drops twice daily for seven days, then 15 drops three times daily until symptoms clear, usually within 28 days. (8) For capsules, liquids, or powders, take the equivalent of 130 milligram GFSE twice a day.

Guidelines for Use

  • Don't confuse GFSE with grape seed extract, an Antioxidant derived from red grapes.

  • GFSE is occasionally sold under such names as "Standardized extract of Grapefruit", "Grapefruit Extract", and "Citrus Seed Extract". Unless otherwise indicated on the label, these products are all usually made from grapefruit seeds only.

General Interaction

Many medications should not be taken with grapefruit juice because they are processed in the body by the same mechanism that processes substances in grapefruit, and the amount of medication and/or its effect may be either increased or decreased. Classes of affected drugs include immunosuppressants, cholesterol-lowering drugs, antihistamines, anti-depressants, hormones, anti-coagulants, steroids, and others. It is not clear whether an extract of the grapefruit's seeds and pulp poses the same risks. If you take any medications, consult the WholeHealthMD drug interaction list, and speak to your doctor about any questions and potential interactions before adding a GFSE supplement.

Possible Side Effects

The risks associated with the use of GFSE are probably low, but little sound research on its effects in humans has been done.


Many of the types of infections for which GFSE is recommended (vaginal yeast infections and intestinal parasites, among others) can cause potentially serious health problems if not treated properly.

Consult a doctor for appropriate diagnosis if you suspect an infection may be present. Avoid using during pregnancy and lactation.



1. Citrosept® Grapefruit extract—History. Available at Accessed February 14, 2012.
2. Grapefruit Seed Extract. Available at Accessed February 11, 2012.
3. Heggers JP, Cottingham J, Gusman J, Reagor L, McCoy L, Carino E, Cox R, Zhao JG. The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity. J Altern Complement Med. 2002 Jun;8(3):333-40.
4. Brzozowski T, Konturek PC, Drozdowicz D, Konturek SJ, Zayachivska O, Pajdo R, Kwiecien S, Pawlik WW, Hahn EG. Grapefruit-seed extract attenuates ethanol-and stress-induced gastric lesions via activation of prostaglandin, nitric oxide and sensory nerve pathways. World J Gastroenterol. 2005 Nov 7;11(41):6450-8.
5. Dembinski A, Warzecha Z, Konturek SJ, Ceranowicz P, Dembinski M, Pawlik WW, Kusnierz-Cabala B, Naskalski JW. Extract of grapefruit-seed reduces acute pancreatitis induced by ischemia/reperfusion in rats: possible implication of tissue antioxidants. J Physiol Pharmacol. 2004 Dec;55(4):811-21.
6. MacCallum DM, Odds FC. Efficacy of parenteral itraconazole against disseminated Candida albicans infection in two mouse strains. J Antimicrob Chemother. 2002 Aug;50(2):225-9.
7. Krajewska-Kułak E, Lukaszuk C, Niczyporuk W. Effects of 33% grapefruit extract on the growth of the yeast--like fungi, dermatopytes and moulds. Wiad Parazytol. 2001;47(4):845-9.
8. Grapefruit Seed Extract and Candida Infections. Available at Accessed February 15, 2012.
9. Vanamala J, Leonardi T, Patil BS, et al. Suppression of colon carcinogenesis by bioactive compounds in grapefruit. Carcinogenesis 27 (6): 1257–65.
10. Adeneye AA. Hypoglycemic and hypolipidemic effects of methanol seed extract of Citrus paradisi Macfad (Rutaceae) in alloxan-induced diabetic Wistar rats. Nig Q J Hosp Med. 2008 Oct-Dec;18(4):211-5.

Evidence Based Rating Scale

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies and what our clinical advisors have found to be efficacious in their personal practice into a visual and easy to interpret format. This tool is meant to simplify the information on supplements and therapies that demonstrate promise in the treatment of certain conditions.




Candida albicans

Animal and laboratory studies indicate potent antifungal properties of GFSE; however, should be used in combination with diet modification. (6-8)


Colon cancer
One animal study shows suppression of colon cancer development; human studies are needed. (9)

One animal study shows GFSE lowers blood glucose levels, triglycerides, LDL ("bad") cholesterol and total cholesterol and increases HDL ("good") cholesterol; human studies are needed. (10)

Date Published: 04/18/2005
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