Does grapefruit juice affect blood pressure?

On its own, a little at most. A 2017 meta-analysis of 3 randomized trials in 250 overweight or obese adults found grapefruit lowered systolic blood pressure by 2.43 mmHg against control (95% CI 0.09 to 4.77). The trials were of moderate quality, lasted 6 to 12 weeks, and pooled the whole fruit with the juice. The effect that is large and well documented is a different one. Grapefruit juice raises the blood levels of some blood pressure drugs, felodipine above all, and that can push pressure lower than the prescriber intended.

Unsettled. The direct effect is unsettled for a plain reason. Three short trials is the whole evidence base, and the upper end of the interval sits at 0.09 mmHg, a hair from no effect. The reviewers themselves write that too few trials, short interventions and no known effective dose limit any conclusion.

How far systolic blood pressure fell, in mmHg

Longer bars mean a bigger fall. The whiskers are 95% confidence intervals, and both of them reach almost to zero. The first row pools whole fruit and juice over 6 to 12 weeks. The second is a single drink taken with beetroot juice, so it cannot show what grapefruit juice does alone. Sources: cards ev-gfjbp-01 and ev-gfjbp-06 below.

What the trials found

Grapefruit itself

The 2017 meta-analysis is the only one that pools grapefruit trials, and its 2.43 mmHg is the figure every later review repeats. A 2026 umbrella review of 25 meta-analyses on flavanones cites it as one of only two positive blood pressure findings for citrus. The same umbrella review found that meta-analyses of citrus juice and of hesperidin supplements showed no significant effect on blood pressure. Those juice trials were mostly orange juice, so they tell you the grapefruit signal has not been confirmed across citrus.

The largest single trial does not show the fall against control. In 74 healthy overweight adults who ate half a fresh grapefruit with each meal for 6 weeks, blood pressure did not differ between the grapefruit and control groups. Systolic pressure in the grapefruit group fell 3.21 mmHg from where it started (P = .03). That is a change within one group, which is not the same as an effect against control, and the trial used the fruit, not the juice.

Juice in a single drink

In a crossover trial in 11 healthy adults, adding 8.5 fl oz (250 mL) of grapefruit juice to beetroot juice lowered systolic pressure by a further 3.3 mmHg at 5 hours (95% CI 0.15 to 6.43) compared with beetroot juice taken with water. That was a single dose combined with nitrate, and the trial had no arm comparing grapefruit juice alone with an active control.

The grapefruit compound as a pill

In a 4-week double-blind trial in 44 overweight adults with fatty liver, a supplement of naringenin, the grapefruit flavanone, did not significantly lower systolic pressure (P = 0.055). That was a pilot study of an isolated compound, and the abstract does not give the dose.

Diet over years

Among 6,599 middle-aged Australian women followed for 15 years, those eating the most flavanones had a lower risk of hypertension, adjusted relative risk 0.83 (95% CI 0.69 to 1.00), with the upper end of the interval at no effect. This is observational and cannot show cause. The flavanones came mainly from oranges and orange juice, not grapefruit.

Who should be careful

Not for everyone. If you take a blood pressure medicine, the juice matters more than any direct effect. Grapefruit juice can block the action of an enzyme in the gut called CYP3A4, the FDA explains, so more of an affected drug enters the blood and stays there longer. The FDA names nifedipine (Procardia, Adalat CC) among the blood pressure drugs it can interact with.

Felodipine and its relatives

The interaction was first reported in a blood pressure study. In 6 men with borderline hypertension, felodipine taken with grapefruit juice reached 284 percent of the level seen with water (range 164 to 469 percent), and diastolic pressure was lower and heart rate higher. That was a very small study, but later randomized work bore it out. In a crossover trial in 12 healthy men, 5.1 fl oz (150 mL) of grapefruit juice just before oral felodipine gave stronger effects of the drug on diastolic pressure and heart rate. A meta-analysis of studies with 13 drugs of this kind, the dihydropyridine calcium channel blockers, names the class as the most prone to the interaction.

Older people are the group the trial authors single out. In 12 healthy people aged 70 to 83, one 8.5 fl oz (250 mL) glass of grapefruit juice raised felodipine exposure 2.9-fold and peak level 4.0-fold, and the size of the interaction varied widely from person to person. The authors write that older people should be particularly cautioned against taking felodipine with grapefruit juice.

Amlodipine, mostly not

Not every drug in the class reacts the same way. In 12 healthy men, a 8.5 fl oz (250 mL) glass of grapefruit juice taken with amlodipine did not change blood pressure or heart rate compared with water. That was a single dose in healthy men, so it does not show what daily juice does in people treated for high blood pressure.

Drugs that the juice weakens

The interaction can run the other way. A 2025 meta-analysis of 51 studies found grapefruit juice cut blood levels of two blood pressure drugs, aliskiren and celiprolol, by about 80 to 90 percent. A drug at a fraction of its usual level may control pressure less well. The same review says most of these studies never measured blood pressure, so how much any of this matters clinically is uncertain.

We found no data on grapefruit juice and blood pressure in pregnancy or in children. That is missing evidence, not a sign of safety. If you take any blood pressure medicine, whether grapefruit juice is safe with your particular drug is a question for your pharmacist or prescriber.

What expert bodies say

The FDA warns that grapefruit juice interacts with some blood pressure drugs and names nifedipine. It gives no figures on how large the effect is. We found no statement from a heart or blood pressure body, such as the American Heart Association, NICE or EFSA, recommending grapefruit juice to lower blood pressure, and the EU register holds no health claim for it.

How we searched

Searched: a local copy of the PubMed 2026 baseline for grapefruit, grapefruit juice, naringin or naringenin with blood pressure, hypertension or blood pressure drugs, which returned 48 records, mostly drug studies. A second search for citrus and orange juice with blood pressure or vascular function returned 45. Europe PMC for systematic reviews, 15 records, which found the 2026 umbrella review. ClinicalTrials.gov, a drug label database, the FDA consumer page and the open web. Search run on 7 October 2026, and the included studies were checked against Retraction Watch.

Included: two meta-analyses and an umbrella review on blood pressure, three randomized trials and one cohort study on grapefruit or its flavanones, five clinical studies of blood pressure drugs taken with the juice, two meta-analyses of those interactions, and the FDA consumer update.

Excluded: drug studies of other calcium channel blockers, which the class meta-analysis covers. Bergamot, mixed citrus and olive extracts and synephrine, which are not grapefruit juice. A meta-analysis of orange juice, whose point is carried by the umbrella review. Reviews of grapes, a different fruit. Commercial and pharmacy blog pages.

What we read: the full text of the 2026 umbrella review, and abstracts for the rest, each confirmed by two separate requests where it was not in our local copy.

What we could not get: the full text of the 2017 meta-analysis, so the per-trial results and its rating of the evidence were not read. The full texts of the 1991 felodipine report, the 2025 interaction meta-analysis, the beetroot trial and the 74-person trial. A 2013 review of grapefruit and medicines that we could read only once, so it is not cited.

What would change this answer

A randomized trial of grapefruit juice in people with high blood pressure, lasting 8 weeks or more, against a drink with the same calories, with 24-hour blood pressure readings. We found no such trial registered on ClinicalTrials.gov.
Studies that measure blood pressure, not only drug levels, in treated patients who drink the juice every day. Most interaction studies stopped at the blood level.
The full data of the 2017 meta-analysis. If the fall came mostly from the fresh fruit trials, the answer for juice would be weaker still.

More on the juice itself: grapefruit juice page.

The food behind this question

Grapefruit juice: an ordinary juice that changes how some drugs work — numbers, evidence and safety

The same question for other foods (blood pressure)

Sources

ev-gfjbp-01 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 250
One hundred and fifty four citations were identified and three RCTs with a total of 250 participants were included. The RCTs were of moderate quality. A meta-analysis for change in body weight failed to reveal a significant difference between grapefruits and controls, MD: -0.45 kg (95% CI: -1.06 to 0.16; I2 = 53%, but analysis revealed a significant decrease in systolic blood pressure, MD: -2.43 mmHg (95% CI: -4.77 to -0.09; I2 = 0%).
Who: overweight and obese adults in randomized clinical trials of grapefruit
Effect: systolic blood pressure MD -2.43 mmHg (95% CI -4.77 to -0.09), I2 0%
Certainty: Only 3 moderate-quality trials of 6 to 12 weeks, fruit and juice pooled; upper CI bound near zero. Full text paywalled.
Critical Reviews in Food Science and Nutrition, 2017, 57(3):602-612 · checked 2026-10-07 · we read the abstract
ev-gfjbp-02 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 250
Paucity in the number of RCTs, short durations of interventions, and lack of an established minimum effective dose limit the conclusions that can be drawn about the effects of grapefruit on body weight and metabolic parameters.
Who: overweight and obese adults in randomized clinical trials of grapefruit
Effect: evidence gap: few RCTs, short duration, no minimum effective dose
Certainty: Authors' own limitation statement.
Critical Reviews in Food Science and Nutrition, 2017, 57(3):602-612 · checked 2026-10-07 · we read the abstract
ev-gfjbp-03 · Meta-analysis or systematic review · umbrella review of meta-analyses of cohorts and RCTs · n = 25 meta-analyses
In addition, Onakpoya et al. [33] reported a significant decrease in systolic blood pressure after grapefruit juice consumption for 6 to 12 weeks [−2.43 mmHg (−4.77; −0.09)].
Who: meta-analyses of flavanone intake and citrus interventions
Effect: grapefruit SBP -2.43 mmHg (-4.77 to -0.09); citrus fruit 0.7 servings/day DBP -3.70 mmHg (-7.02 to -0.38)
Certainty: Secondary synthesis; the grapefruit figure is the same Onakpoya 2017 estimate, not new data.
Epidemiologia (Basel), 2026, 7(4):108 · checked 2026-10-07 · we read the fulltext
ev-gfjbp-04 · Meta-analysis or systematic review · umbrella review of meta-analyses of cohorts and RCTs · n = 25 meta-analyses
No significant results were observed by the other two meta-analyses evaluating hesperidin supplementation and citrus juice interventions [35,38].
Who: meta-analyses of flavanone supplementation and citrus juice interventions
Effect: no significant blood pressure effect in the citrus juice and hesperidin meta-analyses
Certainty: Citrus juice mostly orange juice; shows the grapefruit signal is not confirmed across citrus.
Epidemiologia (Basel), 2026, 7(4):108 · checked 2026-10-07 · we read the fulltext
ev-gfjbp-05 · Randomized controlled trial(s) · randomized controlled trial, 6 weeks · n = 74
No differences between group in weight, blood pressure, or lipids were demonstrated. Grapefruit consumption was associated with modest weight loss (-0.61 ± 2.23 kg, P = .097), a significant reduction in waist circumference (-2.45 ± 0.60 cm, P = .0002), and a significant reduction in systolic blood pressure (-3.21 ± 10.13 mm Hg, P = .03) compared with baseline values.
Who: healthy overweight adults, half a fresh Rio-Red grapefruit with each meal for 6 weeks vs control diet
Effect: no between-group difference in blood pressure; within-group SBP -3.21 ± 10.13 mmHg (P = .03)
Certainty: Whole fruit, not juice; the within-group change is not a comparison with control.
Metabolism, 2012 · checked 2026-10-07 · we read the abstract
ev-gfjbp-06 · Randomized controlled trial(s) · randomized placebo-controlled crossover · n = 11
Peak mean differences in SBP and PP were seen at T = 5 hours: -3.3 mmHg (95% confidence interval [CI] -6.43 to -0.15) and at T = 2.5 hours: -4.2 mmHg (95% CI -0.3 to -8.2), respectively.
Who: healthy volunteers, 2.4 fl oz (70 mL) beetroot juice with 8.5 fl oz (250 mL) grapefruit juice or water, 7-hour visits
Effect: SBP -3.3 mmHg (95% CI -6.43 to -0.15) vs beetroot with water
Certainty: Acute single-dose effect in combination with nitrate; no grapefruit-only arm with active comparison.
Br J Clin Pharmacol, 2021 · checked 2026-10-07 · we read the abstract
ev-gfjbp-07 · Randomized controlled trial(s) · pilot double-blind placebo-controlled randomized trial · n = 44
Furthermore, naringenin supplementation could marginally reduce systolic blood pressure (P = 0.055).
Who: overweight or obese patients with nonalcoholic fatty liver disease, naringenin or placebo for 4 weeks
Effect: systolic blood pressure reduction marginal, P = 0.055
Certainty: Isolated compound, not juice; pilot; dose not in abstract.
Eur J Gastroenterol Hepatol, 2022 · checked 2026-10-07 · we read the abstract
ev-gfjbp-08 · Observational data · prospective cohort study · n = 6599
Higher intakes of flavones [adjusted relative risk (ARR) for quintile 5 vs. 1: 0.82, 95% CI 0.70-0.97], isoflavones (0.86, 0.75-0.99) and flavanones (0.83, 0.69-1.00) were associated with a lower risk of hypertension in the middle-aged cohort.
Who: middle-aged women, Australian Longitudinal Study on Women's Health
Effect: flavanones quintile 5 vs 1 adjusted RR 0.83 (95% CI 0.69 to 1.00)
Certainty: Observational; upper CI bound at 1.00; flavanones came mainly from oranges, not grapefruit.
Eur J Nutr, 2021 · checked 2026-10-07 · we read the abstract
ev-gfjbp-09 · Observational data · crossover clinical pharmacology study · n = 6
Six men with borderline hypertension took felodipine 5 mg with water, grapefruit juice, or orange juice. The mean felodipine bioavailability with grapefruit juice was 284 (range 164-469)% of that with water. The dehydrofelodipine/felodipine AUC ratio was lower, diastolic blood pressure lower, and heart rate higher with grapefruit juice than with water.
Who: men with borderline hypertension, felodipine 5 mg with water, grapefruit juice or orange juice
Effect: felodipine bioavailability 284% (range 164-469%) of water; lower diastolic BP, higher heart rate
Certainty: Randomization not stated in abstract, very small; historic key finding.
Lancet, 1991, 337(8736):268-269 · checked 2026-10-07 · we read the abstract
ev-gfjbp-10 · Randomized controlled trial(s) · randomized crossover single-dose and steady-state study · n = 12
Mean felodipine area under the curve and maximum concentration were 2.9-fold and 4.0-fold greater, respectively, with grapefruit juice in both studies. Interindividual variability in the extent of the interaction was high.
Who: healthy elderly people aged 70 to 83, felodipine 5 mg extended release with 8.5 fl oz (250 mL) grapefruit juice or water
Effect: felodipine AUC 2.9-fold, Cmax 4.0-fold; high interindividual variability
Certainty: Healthy elderly, not treated patients; pharmacokinetic result only.
Clin Pharmacol Ther, 2000 · checked 2026-10-07 · we read the abstract
ev-gfjbp-11 · Randomized controlled trial(s) · randomized crossover single-dose and steady-state study · n = 12
The elderly should be particularly cautioned about concomitant grapefruit juice and felodipine ingestion.
Who: healthy elderly people aged 70 to 83
Effect: advice based on pronounced and unpredictable interaction
Certainty: Authors' conclusion.
Clin Pharmacol Ther, 2000 · checked 2026-10-07 · we read the abstract
ev-gfjbp-12 · Randomized controlled trial(s) · randomized four-way crossover · n = 12
Juice intake immediately before oral felodipine resulted in more pronounced haemodynamic effects of the drug as measured by diastolic blood pressure and heart rate.
Who: healthy men, felodipine 10 mg oral ER or 1.5 mg intravenous, 5.1 fl oz (150 mL) grapefruit juice or water 15 min before
Effect: more pronounced diastolic BP and heart rate effects of oral felodipine
Certainty: Single dose, healthy men.
Eur J Clin Pharmacol, 1997 · checked 2026-10-07 · we read the abstract
ev-gfjbp-13 · Randomized controlled trial(s) · randomized open crossover · n = 12
There were no significant differences in BP and HR between the two treatments.
Who: healthy male volunteers, single 5 mg amlodipine with 8.5 fl oz (250 mL) grapefruit juice or water
Effect: no significant BP or HR difference
Certainty: Single dose, healthy men.
Eur J Clin Pharmacol, 1996 · checked 2026-10-07 · we read the abstract
ev-gfjbp-14 · Meta-analysis or systematic review · meta-analysis of pharmacokinetic studies · n = —
Dihydropyridine calcium channel blockers belong to the category of drugs that are most prone to undergo such interaction.
Who: healthy adults in pharmacokinetic studies of dihydropyridines with grapefruit juice or water
Effect: class most prone to the interaction
Certainty: Pharmacokinetic endpoints only, not blood pressure outcomes.
Curr Pharm Biotechnol, 2012 · checked 2026-10-07 · we read the abstract
ev-gfjbp-15 · Meta-analysis or systematic review · systematic review and meta-analysis of mostly open-label crossover trials · n = 51 studies
Grapefruit juice (GFJ), an inhibitor of organic-anion-transporting polypeptide (OATP) transporters and cytochrome P450 (CYP) 3A4, significantly decreased the AUC and Cmax of aliskiren and celiprolol by approximately 80-90 %.
Who: human pharmacokinetic studies of fruit juices with antihypertensive drugs
Effect: AUC and Cmax of aliskiren and celiprolol down about 80-90%
Certainty: Small samples, moderate quality; hemodynamics mostly not measured.
Complement Ther Med, 2025 · checked 2026-10-07 · we read the abstract
ev-gfjbp-16 · Meta-analysis or systematic review · systematic review and meta-analysis · n = 51 studies
Hemodynamic effects were not assessed in most studies; thus, the clinical significance of these interactions remains uncertain and should be further investigated.
Who: human pharmacokinetic studies of fruit juices with antihypertensive drugs
Effect: evidence gap: hemodynamic effects not assessed in most studies
Certainty: Limitation named by the authors.
Complement Ther Med, 2025 · checked 2026-10-07 · we read the abstract
ev-gfjbp-17 · Position of an expert body · agency consumer update · n = —
Some drugs that treat high blood pressure, such as Procardia and Adalat CC (both nifedipine).
Who: US consumers taking prescription drugs
Effect: —
Certainty: T2 position; does not give effect sizes.
US Food and Drug Administration, Grapefruit Juice and Some Drugs Don't Mix, updated 2021 · checked 2026-10-07 · we read the section
ev-gfjbp-18 · Position of an expert body · agency consumer update · n = —
Grapefruit juice can block the action of intestinal CYP3A4, so instead of being metabolized, more of the drug enters the blood and stays in the body longer.
Who: US consumers taking prescription drugs
Effect: —
Certainty: T2 mechanism statement.
US Food and Drug Administration, Grapefruit Juice and Some Drugs Don't Mix, updated 2021 · checked 2026-10-07 · we read the section

How this page was made. Evidence was extracted from primary sources into cards, every number was re-checked against the source, and the text was written from those cards. Bioma Learn has no human medical reviewer at this time, and we say so rather than invent one. Methodology. This is information, not medical advice.