What does the research show about grapefruit?

Grapefruit

A meta-analysis of 3 trials found no significant weight loss from grapefruit in overweight adults and a 2.4 mmHg fall in systolic blood pressure. Most of the research is on medicines: grapefruit juice raised blood levels of some statins, felodipine, cyclosporine, tacrolimus, buspirone, triazolam, amiodarone, budesonide and oxycodone, and lowered fexofenadine, in controlled studies.

Add to Bio HackChecked 2026-11-13

Status: A food, not a regulated health product. The FDA has required some prescription and over-the-counter drugs taken by mouth to carry warnings against drinking grapefruit juice or eating grapefruit while taking them [1].
Also called: grapefruit juice, Citrus paradisi, pink grapefruit, ruby red grapefruit, grapefruit diet
Studied for: weight loss, fat burning, the grapefruit diet, appetite, blood pressure, cholesterol, insulin resistance, metabolism

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help2

ModerateShown to lower systolic blood pressure by about 2.4 mmHg in overweight adults, in one meta-analysis of 3 small trials.
LimitedOne trial of 91 obese adults found lower insulin 2 hours after a glucose drink with fresh grapefruit before meals than with placebo.

Reported risks9

ModerateThe FDA states grapefruit juice can interact with some statins. One glass daily raised simvastatin levels 3.6-fold in a small trial, and pravastatin was unaffected.How often is not known
ModerateThe FDA states grapefruit juice can interact with nifedipine. In small trials it raised felodipine exposure about 2.5 to 2.9-fold, with lower blood pressure and faster heart rate.How often is not known
LimitedThe FDA states grapefruit juice can interact with cyclosporine. Small trials found higher cyclosporine exposure in volunteers and higher tacrolimus levels in liver transplant patients.How often is not known
LimitedThe FDA states grapefruit juice can interact with buspirone. Small trials found it raised buspirone exposure 9.2-fold and triazolam exposure up to 143%, with more drowsiness.How often is not known
LimitedThe FDA states grapefruit juice can interact with amiodarone. In one small study it raised amiodarone exposure 50% and blocked its main metabolite.How often is not known
LimitedThe FDA states grapefruit juice can interact with budesonide. One small study in 8 men found juice for 4 days about doubled its bioavailability.How often is not known
LimitedThe FDA states grapefruit juice can cause less fexofenadine to enter the blood. In one trial, 300 mL cut its exposure to 58% of that with water.How often is not known
LimitedOne small trial found grapefruit juice for 5 days raised oxycodone exposure 1.7-fold, with self-reported performance impaired and pain relief unchanged.How often is not known
LimitedMixed results: one cohort linked a quarter grapefruit a day to 30% higher breast cancer risk after menopause, and two larger cohorts of women found no link.How often is not known

What it was studied for, and what was found

Shown to help2

Moderate

Blood pressure

Shown to lower systolic blood pressure by about 2.4 mmHg in overweight adults, in one meta-analysis of 3 small trials.

Compared with control groups in 3 randomized trials [2]; a control diet low in fruits and vegetables [4]

The numbers and sources

Effect: Pooled across 3 trials, systolic blood pressure fell more with grapefruit than with controls (MD -2.43 mmHg, 95% CI -4.77 to -0.09, I² 0%) [2]. In the 6-week trial, blood pressure did not differ between groups, and systolic pressure fell 3.21 mmHg from baseline in the grapefruit group (P = .03) [4].
Population: 250 overweight and obese adults in 3 trials [2]. 74 overweight adults [4].
Sources: [2], [4]
Caveats: The upper end of the pooled interval sits close to zero, and the trials were short [2]. The 6-week trial found no difference against its control group [4].

Limited

Insulin resistance

One trial of 91 obese adults found lower insulin 2 hours after a glucose drink with fresh grapefruit before meals than with placebo.

Compared with placebo capsules with apple juice [3]

The numbers and sources

Effect: After 12 weeks, 2-hour post-glucose insulin fell significantly in the fresh grapefruit group compared with placebo [3].
Population: 91 obese adults for 12 weeks [3].
Sources: [3]
Caveats: One small trial, and the abstract gives no size for the change in insulin.

Mixed results1

Limited

Cholesterol

Mixed results: one trial found HDL cholesterol rose with grapefruit against a water preload, while another found no difference in blood lipids against a control diet.

Compared with a control diet low in fruits and vegetables [4]; a water preload matched for weight and calories [5]

The numbers and sources

Effect: Over 12 weeks, HDL cholesterol changed by +6.2% with grapefruit and +8.2% with grapefruit juice preloads, against -3.7% with water (significant) [5]. Over 6 weeks, lipids did not differ between the grapefruit and control groups, though total cholesterol fell 11.7 mg/dL and LDL cholesterol 18.7 mg/dL from baseline in the grapefruit group [4].
Population: 85 obese adults on calorie restriction [5]. 74 overweight adults [4].
Sources: [5], [4]
Caveats: Two small trials with different comparisons. Changes from baseline within one group do not show an effect of grapefruit when the control group is not different [4].

Not shown to help1

Moderate

Body weight

Not shown to lower body weight in overweight adults in one meta-analysis of 3 trials. One trial found 1.3 kg more loss with fresh grapefruit than placebo.

Compared with control groups in 3 randomized trials [2]; placebo capsules with apple juice [3]; a control diet low in fruits and vegetables [4]; a water preload matched for weight and calories [5]

The numbers and sources

Effect: Across 3 randomized trials with 250 participants, weight change did not differ between grapefruit and controls (MD -0.45 kg, 95% CI -1.06 to 0.16, I² 53%) [2]. In one of them, after 12 weeks the fresh grapefruit group lost 1.6 kg, the grapefruit juice group 1.5 kg, the grapefruit capsule group 1.1 kg and the placebo group 0.3 kg. The fresh grapefruit group lost significantly more than placebo (P < .05) [3]. Half a grapefruit with each meal for 6 weeks did not change weight against a control diet, with a change of -0.61 kg from baseline (P = .097) [4]. In 85 obese adults on calorie restriction, weight fell 7.1% overall over 12 weeks, with no difference between grapefruit, grapefruit juice and water preloads [5].
Population: 250 overweight and obese adults in 3 trials [2]. 91 obese adults for 12 weeks [3]. 74 overweight adults for 6 weeks [4]. 85 obese adults for 12 weeks [5].
Sources: [2], [3], [4], [5]
Caveats: Few trials, all short, and the reviewers note no established minimum dose [2]. The water preload trial matched preloads for calories, so it tested grapefruit against another low-energy food, not against eating nothing [5].

Amounts studied

The weight trials used half a fresh grapefruit three times a day before meals for 6 to 12 weeks [3][4], 8 ounces (237 mL) of grapefruit juice before each meal [3], or a 127 g grapefruit preload before each meal [5]. Drug interaction studies used 200 mL of double-strength juice three times a day for 2 days [6][7], one 200 mL glass a day for 3 days [8], 300 mL a day for 90 days [9], a single 250 mL glass [10], a single 240 mL glass [11], one glass of regular or double-strength juice or double-strength juice three times a day [12][13], three 300 mL glasses on one day [14], 200 mL three times a day for 4 to 5 days [15][16], and 300 mL against 1,200 mL [17].

Risks

Reported risks8

ModerateHow often is not known

Higher blood levels of some statins

The FDA states grapefruit juice can interact with some statins. One glass daily raised simvastatin levels 3.6-fold in a small trial, and pravastatin was unaffected.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA names simvastatin and atorvastatin among drugs grapefruit juice can interact with, and states that too much statin in the body raises the risk of liver and muscle damage [1]. Double-strength juice three times a day raised simvastatin exposure (AUC) 16-fold [6]. One 200 mL glass a day for 3 days raised simvastatin AUC 3.6-fold and simvastatin acid 3.3-fold [8]. Double-strength juice raised atorvastatin acid AUC 2.5-fold, and did not change pravastatin [7]. In 60 patients who kept their atorvastatin dose and added 300 mL a day for 90 days, serum atorvastatin rose 19% to 26%, lipids changed negligibly, and liver tests and creatine phosphokinase showed no adverse effects [9]. A modeling review estimated a daily glass raises simvastatin and lovastatin blood levels about 260% when taken together and atorvastatin about 80%, and judged the added rhabdomyolysis risk minimal [18].
Population: 10 healthy volunteers [6]. 10 healthy volunteers [8]. 12 and 11 healthy volunteers [7]. 130 patients on stable atorvastatin [9]. A modeling analysis [18].
Sources: [1], [6], [8], [7], [9], [18]
Caveats: The pharmacokinetic studies were small and in healthy volunteers, and none measured muscle injury. The size of the interaction depended on the amount of juice and the statin [6][8][7].

ModerateHow often is not known

Higher blood levels of some calcium channel blockers

The FDA states grapefruit juice can interact with nifedipine. In small trials it raised felodipine exposure about 2.5 to 2.9-fold, with lower blood pressure and faster heart rate.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA names nifedipine among drugs grapefruit juice can interact with [1]. With grapefruit juice, felodipine bioavailability was 284% of that with water, diastolic blood pressure was lower, heart rate higher, and side effects from blood vessel widening more frequent. Nifedipine bioavailability was 134% of that with water [19]. Felodipine AUC rose from 53 with water to 130 nmol.h/L with grapefruit juice [20]. In adults aged 70 to 83, felodipine AUC was 2.9-fold and peak concentration 4.0-fold higher with 250 mL of juice. Blood pressure was lower in the single-dose study, and heart rate was higher in both studies [10].
Population: 6 men with borderline hypertension and 6 healthy men [19]. 12 healthy men [20]. 12 healthy adults aged 70 to 83 [10].
Sources: [1], [19], [20], [10]
Caveats: Small studies of single or short courses. The size of the interaction varied widely between people [10].

LimitedHow often is not known

Higher blood levels of transplant drugs

The FDA states grapefruit juice can interact with cyclosporine. Small trials found higher cyclosporine exposure in volunteers and higher tacrolimus levels in liver transplant patients.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA names cyclosporine (Neoral, Sandimmune) among drugs grapefruit juice can interact with [1]. With 240 mL of grapefruit juice, median dose-corrected cyclosporine AUC was 15.6 against 11.3 with orange juice (P ≤ 0.007), and juice free of furanocoumarins showed no such rise [11]. In liver transplant patients, tacrolimus blood levels rose by 1.56 and 10.33 ng/mL after a week of two kinds of grapefruit juice, and one group needed 2.3 mg a day less tacrolimus [21].
Population: 18 healthy volunteers [11]. 30 liver transplant patients in 3 groups [21].
Sources: [1], [11], [21]
Caveats: Small studies. The tacrolimus trial used juice on purpose to raise levels under monitoring [21].

LimitedHow often is not known

Higher blood levels of a sleep drug and an anti-anxiety drug

The FDA states grapefruit juice can interact with buspirone. Small trials found it raised buspirone exposure 9.2-fold and triazolam exposure up to 143%, with more drowsiness.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA names buspirone among drugs grapefruit juice can interact with [1]. One glass of regular-strength juice raised triazolam AUC by 53%, and double-strength juice three times a day for days raised it by 143% and lengthened its half-life by 54%, with more subjective drowsiness and a lower digit symbol test score [12]. Double-strength juice raised buspirone AUC 9.2-fold (range 3 to 20.4-fold) and peak concentration 4.3-fold [13].
Population: 12 healthy volunteers [12]. 10 healthy volunteers [13].
Sources: [1], [12], [13]
Caveats: Single doses of each drug in healthy volunteers. Only subjective overall drug effect rose with buspirone [13].

LimitedHow often is not known

Higher blood levels of amiodarone

The FDA states grapefruit juice can interact with amiodarone. In one small study it raised amiodarone exposure 50% and blocked its main metabolite.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA names amiodarone (Pacerone, Cordarone) among drugs grapefruit juice can interact with [1]. Three 300 mL glasses on the day of a single dose raised amiodarone AUC by 50% and peak concentration by 84%, and completely stopped production of its main metabolite. Amiodarone's changes to the PR and QTc intervals of the heart tracing were smaller with grapefruit juice [14].
Population: 11 healthy adults, compared with their own earlier test [14].
Sources: [1], [14]
Caveats: One study, one dose, not randomized, with the comparison period 6 months earlier [14].

LimitedStudied in menHow often is not known

Higher blood levels of budesonide

The FDA states grapefruit juice can interact with budesonide. One small study in 8 men found juice for 4 days about doubled its bioavailability.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA names budesonide (Entocort EC, Uceris) among drugs grapefruit juice can interact with [1]. Regular-strength juice, 200 mL three times a day for 4 days, about doubled the bioavailability of both plain and extended-release budesonide capsules [15].
Population: 8 healthy men [15].
Sources: [1], [15]
Caveats: One small open study, with a corresponding author at AstraZeneca, the maker of a budesonide product [15].

LimitedHow often is not known

Lower blood levels of fexofenadine

The FDA states grapefruit juice can cause less fexofenadine to enter the blood. In one trial, 300 mL cut its exposure to 58% of that with water.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The FDA states grapefruit juice can lower the amount of fexofenadine (Allegra) entering the blood, by acting on drug transporters, and that its label says not to take it with fruit juices [1]. With 300 mL of grapefruit juice, fexofenadine AUC fell to 58% and peak concentration to 53% of the values with water. With 1,200 mL, they fell to 36% and 33% [17].
Population: 12 healthy volunteers [17].
Sources: [1], [17]
Caveats: One small crossover study measured blood levels, not allergy symptoms.

LimitedHow often is not known

Higher blood levels of oxycodone

One small trial found grapefruit juice for 5 days raised oxycodone exposure 1.7-fold, with self-reported performance impaired and pain relief unchanged.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: Grapefruit juice, 200 mL three times a day for 5 days, raised oxycodone AUC 1.7-fold, peak concentration 1.5-fold and half-life 1.2-fold against water. Self-reported performance was impaired, and pain relief did not change [16].
Population: 12 healthy volunteers in a randomized crossover [16].
Sources: [16]
Caveats: One trial of a single 10 mg dose in healthy volunteers.

Mixed results1

LimitedStudied in womenHow often is not known

Breast cancer

Mixed results: one cohort linked a quarter grapefruit a day to 30% higher breast cancer risk after menopause, and two larger cohorts of women found no link.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: Among postmenopausal women, a quarter grapefruit or more a day was linked to higher breast cancer risk than eating none (RR 1.30, 95% CI 1.06 to 1.58) [22]. In the Nurses' Health Study, a quarter grapefruit or more a day was not linked to breast cancer (RR 1.00, 95% CI 0.86 to 1.15), nor was grapefruit juice [23]. In EPIC, women eating 60 g or more a day had no higher risk than women eating none (HR 0.93, 95% CI 0.77 to 1.13) [24].
Population: Over 50,000 postmenopausal women with 1,657 cases [22]. 77,050 women with 4,315 cases [23]. 114,504 women followed a median 9.5 years, with 3,747 cases [24].
Sources: [22], [23], [24]
Caveats: Observational studies of reported diet, open to confounding. Two larger cohorts did not repeat the first finding [23][24].

Claims tested and not found

That eating grapefruit causes weight loss. A meta-analysis of 3 trials found no significant difference in weight against controls [2], and grapefruit preloads did not differ from water preloads matched for calories [5].
That grapefruit juice raises blood levels of every statin. Pravastatin levels did not change with double-strength grapefruit juice [7].

Statins Calcium channel blockers Benzodiazepines

Sources

U.S. Food and Drug Administration. Grapefruit Juice and Some Drugs Don't Mix. Consumer Update. 2021. https://www.fda.gov/consumers/consumer-updates/grapefruit-juice-and-some-drugs-dont-mix
Onakpoya I, O'Sullivan J, Heneghan C, Thompson M. The effect of grapefruits (Citrus paradisi) on body weight and cardiovascular risk factors: A systematic review and meta-analysis of randomized clinical trials. Critical Reviews in Food Science and Nutrition. 2017. https://doi.org/10.1080/10408398.2014.901292
Fujioka K, Greenway F, Sheard J, Ying Y. The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome. Journal of Medicinal Food. 2006. https://doi.org/10.1089/jmf.2006.9.49
Dow CA, Going SB, Chow HH, et al. The effects of daily consumption of grapefruit on body weight, lipids, and blood pressure in healthy, overweight adults. Metabolism. 2012. https://doi.org/10.1016/j.metabol.2011.12.004
Silver HJ, Dietrich MS, Niswender KD. Effects of grapefruit, grapefruit juice and water preloads on energy balance, weight loss, body composition, and cardiometabolic risk in free-living obese adults. Nutrition & Metabolism. 2011. https://doi.org/10.1186/1743-7075-8-8
Lilja JJ, Kivistö KT, Neuvonen PJ. Grapefruit juice-simvastatin interaction: effect on serum concentrations of simvastatin, simvastatin acid, and HMG-CoA reductase inhibitors. Clinical Pharmacology and Therapeutics. 1998. https://doi.org/10.1016/s0009-9236(98)90130-8
Lilja JJ, Kivistö KT, Neuvonen PJ. Grapefruit juice increases serum concentrations of atorvastatin and has no effect on pravastatin. Clinical Pharmacology and Therapeutics. 1999. https://doi.org/10.1053/cp.1999.v66.100453001
Lilja JJ, Neuvonen M, Neuvonen PJ. Effects of regular consumption of grapefruit juice on the pharmacokinetics of simvastatin. British Journal of Clinical Pharmacology. 2004. https://doi.org/10.1111/j.1365-2125.2004.02095.x
Reddy P, Ellington D, Zhu Y, et al. Serum concentrations and clinical effects of atorvastatin in patients taking grapefruit juice daily. British Journal of Clinical Pharmacology. 2011. https://doi.org/10.1111/j.1365-2125.2011.03996.x
Dresser GK, Bailey DG, Carruthers SG. Grapefruit juice-felodipine interaction in the elderly. Clinical Pharmacology and Therapeutics. 2000. https://doi.org/10.1067/mcp.2000.107524
Paine MF, Widmer WW, Pusek SN, et al. Further characterization of a furanocoumarin-free grapefruit juice on drug disposition: studies with cyclosporine. The American Journal of Clinical Nutrition. 2008. https://doi.org/10.1093/ajcn/87.4.863
Lilja JJ, Kivistö KT, Backman JT, Neuvonen PJ. Effect of grapefruit juice dose on grapefruit juice-triazolam interaction: repeated consumption prolongs triazolam half-life. European Journal of Clinical Pharmacology. 2000. https://doi.org/10.1007/s002280000156
Lilja JJ, Kivistö KT, Backman JT, et al. Grapefruit juice substantially increases plasma concentrations of buspirone. Clinical Pharmacology and Therapeutics. 1998. https://doi.org/10.1016/s0009-9236(98)90056-x
Libersa CC, Brique SA, Motte KB, et al. Dramatic inhibition of amiodarone metabolism induced by grapefruit juice. British Journal of Clinical Pharmacology. 2000. https://doi.org/10.1046/j.1365-2125.2000.00163.x
Seidegård J, Randvall G, Nyberg L, Borgå O. Grapefruit juice interaction with oral budesonide: equal effect on immediate-release and delayed-release formulations. Die Pharmazie. 2009. https://pubmed.ncbi.nlm.nih.gov/19694184/
Nieminen TH, Hagelberg NM, Saari TI, et al. Grapefruit juice enhances the exposure to oral oxycodone. Basic & Clinical Pharmacology & Toxicology. 2010. https://doi.org/10.1111/j.1742-7843.2010.00582.x
Dresser GK, Kim RB, Bailey DG. Effect of grapefruit juice volume on the reduction of fexofenadine bioavailability: possible role of organic anion transporting polypeptides. Clinical Pharmacology and Therapeutics. 2005. https://doi.org/10.1016/j.clpt.2004.10.005
Lee JW, Morris JK, Wald NJ. Grapefruit Juice and Statins. The American Journal of Medicine. 2016. https://doi.org/10.1016/j.amjmed.2015.07.036
Bailey DG, Spence JD, Munoz C, Arnold JM. Interaction of citrus juices with felodipine and nifedipine. The Lancet. 1991. https://doi.org/10.1016/0140-6736(91)90872-m
Bailey DG, Kreeft JH, Munoz C, et al. Grapefruit juice-felodipine interaction: effect of naringin and 6',7'-dihydroxybergamottin in humans. Clinical Pharmacology and Therapeutics. 1998. https://doi.org/10.1016/s0009-9236(98)90173-4
Liu C, Shang YF, Zhang XF, et al. Co-administration of grapefruit juice increases bioavailability of tacrolimus in liver transplant patients: a prospective study. European Journal of Clinical Pharmacology. 2009. https://doi.org/10.1007/s00228-009-0702-z
Monroe KR, Murphy SP, Kolonel LN, Pike MC. Prospective study of grapefruit intake and risk of breast cancer in postmenopausal women: the Multiethnic Cohort Study. British Journal of Cancer. 2007. https://doi.org/10.1038/sj.bjc.6603880
Kim EH, Hankinson SE, Eliassen AH, Willett WC. A prospective study of grapefruit and grapefruit juice intake and breast cancer risk. British Journal of Cancer. 2008. https://doi.org/10.1038/sj.bjc.6604105
Spencer EA, Key TJ, Appleby PN, et al. Prospective study of the association between grapefruit intake and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC). Cancer Causes & Control. 2009. https://doi.org/10.1007/s10552-009-9310-6

Everything in the library

Shown to help2

Reported risks9

What it was studied for, and what was found

Shown to help2

Mixed results1

Not shown to help1

Amounts studied

Risks

Reported risks8

Mixed results1

Claims tested and not found

Related

Sources