Fruits · Fruit
Grapefruit
Citrus x paradisi · also called Pink grapefruit, white grapefruit, toronja (Spanish)
Grapefruit is a tart citrus fruit; the juicy sections are eaten or squeezed for juice. A cup of sections has about 74 calories and 79 mg of vitamin C. Trials of grapefruit products found no useful weight loss and only a very small blood pressure change. The most important caution: grapefruit and grapefruit juice can change how some medicines work, so check with a pharmacist if you take any regular medicine.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Grapefruit
Grapefruit is a low-calorie, vitamin C-rich citrus fruit. It is an everyday food with thin evidence for health benefits and one well-documented caution: it can change how some medicines work.
What it is
Grapefruit is the fruit of Citrus x paradisi, a citrus tree in the rue family (Rutaceae), the same family as oranges, lemons and limes. The juicy sections inside the peel are eaten or squeezed for juice. The botanical database GBIF lists the name as a synonym of Citrus x aurantium, but food and medical sources still use Citrus x paradisi for grapefruit.
A cup of raw sections with juice (230 g) provides about 74 calories, 2.5 g of fibre, 16.1 g of natural sugars, 79 mg of vitamin C and 320 mg of potassium, with no vitamin K (USDA, calculated from the per-100 g values). Half a medium grapefruit (128 g) provides about 41 calories and 44 mg of vitamin C.
What the research shows
A review of 3 short trials of grapefruit products in 250 overweight or obese adults found no significant change in body weight and a very small fall in systolic blood pressure. The authors say few, short trials limit the conclusions.
Studies of eating habits link citrus fruit in general with lower risk of one type of oesophageal cancer and with slightly higher skin cancer risk. They cannot show cause and they do not single out grapefruit. Kidney-stone results for grapefruit juice are mixed. MedlinePlus says vitamin C does not lower the chance of catching a cold for most people.
Whole fruit versus juice and extracts
Most medicine warnings and the heart-rhythm trial are about grapefruit juice, and the FDA says both juice and the fruit can affect medicines. Juice has less fibre than the fruit. Seed and peel extracts and capsules are different products that the sources we read did not cover, so we make no claim about them.
At a glance
Traditional uses history, not proof
- Eaten fresh in halves or sections, or squeezed for juice
- Grapefruit diets are a popular idea; no source we read documents where they began
Studied for research
- Vitamin C supply and scurvy, moderate certainty (a nutrient fact, not a grapefruit trial)
- Body weight, low certainty (no significant change)
- Blood pressure, very low certainty
- Oesophageal cancer risk (citrus in the diet), very low certainty
- Skin cancer risk (citrus in the diet), very low certainty, a possible harm signal
- Kidney stones (grapefruit juice), mixed
Main compounds
- Vitamin C (about 79 mg in a cup of sections)
- Dietary fibre (about 2.5 g per cup)
- Potassium (about 320 mg per cup)
- Beta-carotene and lycopene pigments
- Furocoumarins, sun-sensitising plant compounds found in citrus
Common forms
- Fresh sections or halves (the form the nutrition figures describe)
- Canned or jarred sections
- Grapefruit juice (less fibre; most medicine warnings and the heart-rhythm trial are about juice)
- Seed, peel and capsule products (not the same as the fruit, and not covered here)
Research links: FDA: Grapefruit Juice and Some Drugs Don't Mix · NHS: Simvastatin · Grapefruit, body weight and blood pressure, meta-analysis (Critical Reviews in Food Science and Nutrition, 2017) · USDA FoodData Central: raw grapefruit · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Citrus x paradisi (grapefruit)
- Naming authority
- Macfad. (GBIF lists it as a synonym of Citrus x aurantium L., usageKey 8077391)
- Synonyms
- Citrus paradisi (the older spelling used by USDA and by the meta-analysis title)
- Common names
- Grapefruit (English); Pink grapefruit (English); White grapefruit (English); Toronja / pomelo rosado (Spanish)
- Family or group
- Rutaceae (rue or citrus family), which also includes oranges, lemons, limes and pomelo.
- Classification
- Plantae > Tracheophyta > Magnoliopsida > Sapindales > Rutaceae > Citrus > Citrus x paradisi
- Native range
- Not verified from a source read.
- Habitat
- Not verified.
- What it looks like
- Roots: Not verified.; Stems: Not verified.; Leaves: Not verified.; Flowers: Not verified.; Fruit: A citrus fruit: the juicy sections inside the peel are eaten or squeezed for juice (existing site summary; not re-sourced).
- Cultivation
- Not verified from a source read.
- Harvest and processing
- Eaten fresh in halves or sections, as canned or jarred sections, or as juice (existing site summary).
- Look-alikes and adulterants
- Name: Pomelo, Seville orange, tangelo; Note: The FDA says Seville oranges, pomelos and tangelos (a cross of tangerine and grapefruit) might affect medicines the same way as grapefruit juice.; Name: Orange, lemon, lime; Note: Other citrus fruits. Results for 'citrus' in studies mix these fruits together.
- Sustainability and conservation
- Not assessed.
Photographs
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Everyday fruit and diet fad | Eaten fresh and as juice. Grapefruit diets are a popular idea; no source read documents their origin, and trials found no useful weight loss. | NOT verified (no source read) |
Traditional use shows how it was used. It does not show that it works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Vitamin C | vitamin | Flesh and juice 34.4 mg per 100 g; about 79 mg in one cup of sections (USDA) | Essential nutrient that prevents scurvy. 15 13 | Composition data and reference article |
| Dietary fibre | carbohydrate | Flesh 1.1 g per 100 g; about 2.5 g per cup of sections (USDA) | Provides fibre in the diet. Juice has less fibre than the fruit. 15 | Composition data |
| Beta-carotene and lycopene | carotenoid pigments | Flesh (amounts in the USDA item for pink, red and white grapefruit combined) Beta-carotene 552 micrograms and lycopene 1,140 micrograms per 100 g (USDA) | No grapefruit trial of these compounds was found in the sources read. 15 | Composition data |
| Furocoumarins | plant compounds found in citrus | Not stated in the sources read | Make skin more sensitive to sunlight when applied to the skin, and are a suspected reason for the citrus and skin cancer link. 4 5 | Epidemiology and lab background |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Intestinal CYP3A4 enzyme | CYP3A4 | Grapefruit juice can block this gut enzyme, so more of some medicines enters the blood. A 2024 review says this is the critical route for most reported interactions with mental-health medicines, but not the only one. 9 7 | Human (FDA summary and review) |
| Drug transporters | Grapefruit juice can affect transport proteins, which the FDA says lowers the amount of fexofenadine entering the blood. 9 | Human (FDA summary) |
Absorption, metabolism and elimination
- Absorption
- Not researched for the fruit's own compounds.
- Distribution
- Not found.
- Metabolism
- Grapefruit juice affects how medicines are broken down by CYP3A4 in the gut wall; it is the medicines, not the fruit compounds, that are described.
- Elimination
- Not found.
- Bioavailability
- Not established for the fruit's own compounds.
Isolated compounds versus whole extracts
Most interaction warnings and the QT trial are about grapefruit juice, and the FDA says grapefruit juice and grapefruit can both affect medicines. Weight and blood-pressure trials tested grapefruit products without saying which form. Seed or peel extracts, capsules and essential oil were not covered by the sources read, so nothing is claimed about them.
Nutritional composition
Per 100 g of raw grapefruit, pink, red and white (USDA FoodData Central 173033, SR Legacy, last updated 2019): 32 kcal, 90.9 g water, 0.63 g protein, 0.1 g fat, 8.08 g carbohydrate of which 6.98 g are sugars, and 1.1 g fibre. One cup of sections with juice (230 g) provides about 74 kcal, 2.5 g fibre and 16.1 g sugars, plus about 79 mg of vitamin C, 320 mg of potassium, 23 micrograms of folate (DFE), 106 micrograms of vitamin A (RAE) and no vitamin K. Half a medium grapefruit (128 g) provides about 41 kcal, 1.4 g fibre and 44 mg of vitamin C. Per-portion figures are calculated from the per-100 g values. Values vary with variety, ripeness and storage, and grapefruit juice has less fibre than the fruit.
1 moderate certainty1 mixed findings2 low certainty3 very low certainty
What was looked at
The 7 benefits and uses checked for Grapefruit, each with how strong the evidence is. Tap one to open it.
- Body weight (grapefruit products in overweight adults)Low certainty
- Blood pressure (grapefruit products in overweight adults)Very low certainty
- Vitamin C supply and scurvy (deficiency)Moderate certainty
- Colds (vitamin C from food or supplements)Low certainty
- Oesophageal (food-pipe) cancer risk (citrus fruit in the diet)Very low certainty
- Skin cancer risk (citrus in the diet): a possible harm signalVery low certainty
- Kidney stones (grapefruit juice)Mixed findings
Lab markers tracked in the studies
Body weightSystolic blood pressureUrine citrateUrine oxalate
What is Grapefruit good for?
The main studied uses and how strong the human evidence is for each. Most results are small changes in lab markers or links seen in eating habits, not proof that grapefruit prevents or treats a disease.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Body weight (grapefruit products in overweight adults)
Low certaintyIn three short trials of grapefruit products in 250 overweight or obese adults, body weight did not differ significantly from the control groups. The average difference was under half a kilogram and the range included no change.
1 studiesThe abstract does not say which forms were used (fruit, juice or caps…
Studies, doses and limits
What the trials found
A 2017 systematic review and meta-analysis pooled 3 randomised trials (250 people) of grapefruit in overweight or obese adults.
Results
No significant difference in body weight versus controls.
Effect sizes as reported
Mean difference -0.45 kg (95% CI -1.06 to 0.16; I2 = 53%).
Why this rating
Only 3 short trials of moderate quality. The result is null, not proof of no effect, but there is no evidence of a useful weight change.
Form and dose studied
The abstract does not say which forms were used (fruit, juice or capsules), so the result may not apply to the plain fruit.
Who was studied
Overweight and obese adults only.
Limits
Few trials, short, forms not given in the abstract.
Why researchers looked
Grapefruit is a low-calorie, juicy fruit that has long been promoted in weight-loss diets, so researchers tested it.
Traditional use
Grapefruit diets have a long popular history. No source we read documents where the idea began.
Proposed mechanism Unknown
Not established. Ideas about blood sugar or insulin effects were not tested in the review we read.
A proposed mechanism does not show that the effect happens in people.
Grapefruit and grapefruit juice can change how some medicines work. See the safety tab before using it in any diet.
Blood pressure (grapefruit products in overweight adults)
Very low certaintyThe same trials found a very small fall in the top blood pressure number. The change was only about 2 mmHg and its range only just stayed below zero. The authors say they cannot draw firm conclusions.
2 studiesGrapefruit products (the abstract does not specify fruit, juice or ca…
Studies, doses and limits
What the trials found
The 2017 meta-analysis of 3 randomised trials (250 overweight or obese adults) also looked at blood pressure.
Results
A small average fall in systolic pressure. Authors cite too few trials, short duration and no established minimum effective amount.
Effect sizes as reported
Systolic blood pressure -2.43 mmHg (95% CI -4.77 to -0.09; I2 = 0%).
Why this rating
Three short trials, a confidence interval that nearly touches zero, a marker rather than a heart outcome, and unclear forms of grapefruit.
Form and dose studied
Grapefruit products (the abstract does not specify fruit, juice or capsules).
Who was studied
Overweight and obese adults.
Limits
Marker only; no heart attacks or strokes measured. Diastolic result not given in the abstract.
Why researchers looked
Grapefruit provides potassium and plant compounds, so blood pressure was one of the outcomes checked.
Proposed mechanism Unknown
Not established.
A proposed mechanism does not show that the effect happens in people.
People taking blood pressure medicine should know grapefruit can change the effect of some of them (nifedipine is a named example).
Vitamin C supply and scurvy (deficiency)
Moderate certaintyGrapefruit is one of the citrus fruits listed among the best food sources of vitamin C. Severe vitamin C deficiency causes scurvy, which mainly affects older, malnourished adults. Eating vitamin C-rich foods meets the need; there is no sign of extra benefit beyond that.
2 studiesWhole fruit; the figures describe raw grapefruit.
Studies, doses and limits
What the trials found
MedlinePlus (reviewed January 2025) lists orange and grapefruit among fruits with the highest vitamin C content. USDA gives 34.4 mg per 100 g of raw grapefruit.
Results
Grapefruit supplies vitamin C. No trial of grapefruit itself against deficiency was found.
Effect sizes as reported
One cup of sections (230 g) has about 79 mg of vitamin C (USDA, calculated).
Why this rating
Reference sources agree on the nutrient. This is about the nutrient, not a trial of grapefruit.
Form and dose studied
Whole fruit; the figures describe raw grapefruit.
Who was studied
General population.
Limits
Not a grapefruit trial. Cooking, storage and light can lower vitamin C.
Why researchers looked
Citrus fruits were the classic food for preventing scurvy.
Traditional use
Citrus fruit for scurvy is a long-standing practice; no source we read gives its history.
Proposed mechanism Established physiology
Vitamin C is an essential nutrient the body cannot store.
A proposed mechanism does not show that the effect happens in people.
None specific to this finding.
Colds (vitamin C from food or supplements)
Low certaintyMedlinePlus says that for most people vitamin C supplements or vitamin C-rich foods do not lower the chance of catching a cold. People who take vitamin C supplements regularly might have slightly shorter or milder colds.
1 studiesVitamin C supplements and vitamin C-rich foods in general.
Studies, doses and limits
What the trials found
MedlinePlus (reviewed January 2025) summarises research on vitamin C and the common cold in general.
Results
No reduction in the chance of catching a cold for most people. Not a grapefruit trial.
Effect sizes as reported
No numbers given in the page read.
Why this rating
A reference summary of vitamin C research, not a trial of grapefruit.
Form and dose studied
Vitamin C supplements and vitamin C-rich foods in general.
Who was studied
General population.
Limits
Not grapefruit-specific.
Why researchers looked
Vitamin C is a popular household remedy for colds, and grapefruit is a vitamin C food.
Traditional use
Vitamin C for colds is a popular household remedy.
Proposed mechanism Unknown
Not established.
A proposed mechanism does not show that the effect happens in people.
None specific.
Oesophageal (food-pipe) cancer risk (citrus fruit in the diet)
Very low certaintyIn a pooled analysis of mostly case-control studies, people who ate more citrus fruit had a lower risk of the squamous cell type of oesophageal cancer, but not of adenocarcinoma. This is a link seen in eating habits, and grapefruit is not separated from other citrus.
1 studiesCitrus fruit as eaten; grapefruit alone is not shown.
Studies, doses and limits
What the trials found
A 2018 meta-analysis pooled 25 studies (20 case-control, 5 cohort) with 5,730 people who had oesophageal cancer.
Results
Lower risk with more citrus fruit overall and for squamous cell cancer; no clear link for adenocarcinoma.
Effect sizes as reported
All: RR 0.65 (95% CI 0.56-0.75). Squamous cell: RR 0.59 (0.47-0.76). Adenocarcinoma: RR 0.86 (0.74-1.01).
Why this rating
Mostly case-control studies, which are weak for showing cause, and people with cancer may remember diet differently. Citrus fruit of all kinds is grouped together.
Form and dose studied
Citrus fruit as eaten; grapefruit alone is not shown.
Who was studied
Adults in observational studies.
Limits
Association only. Not a grapefruit result.
Why researchers looked
Citrus fruits contain vitamin C and plant compounds, so researchers asked whether eating them is linked with cancer.
Proposed mechanism Unknown
Not tested in the review. Authors call for studies of the citrus compounds.
A proposed mechanism does not show that the effect happens in people.
None specific.
Skin cancer risk (citrus in the diet): a possible harm signal
Very low certaintyIn a large European study, people who ate the most citrus had a slightly higher chance of skin cancer than those who ate the least. A review of dietary furocoumarins, sun-sensitising plant compounds found in citrus, rated the evidence for a melanoma link as moderate but could not say how much intake matters. These are links, not proof that grapefruit causes skin cancer.
2 studiesCitrus fruit and juice as eaten; furocoumarin-rich foods in general.
Studies, doses and limits
What the trials found
A 2020 cohort of 270,112 adults (EPIC) and a 2025 systematic review of 19 studies on dietary furocoumarins.
Results
Slightly higher skin cancer risk with higher citrus intake in EPIC. The review found moderate evidence for a risk link for higher furocoumarin intake overall, with no pooled figure.
Effect sizes as reported
EPIC, highest vs lowest quarter: total citrus HR 1.10 (95% CI 1.03-1.18); citrus fruit and melanoma HR 1.23 (1.02-1.48).
Why this rating
Observational. Sun exposure and other habits can confuse the result, and the authors of both papers say better exposure data are needed. Grapefruit is not separated in the abstracts.
Form and dose studied
Citrus fruit and juice as eaten; furocoumarin-rich foods in general.
Who was studied
Adults in cohort studies.
Limits
Association only. The size of the grapefruit contribution is not stated.
Why researchers looked
Furocoumarins make skin more sensitive to sunlight when applied to the skin, so researchers asked if eating them matters.
Proposed mechanism Preliminary mechanism
Furocoumarins interact with ultraviolet light and can stimulate melanoma cells in the lab, as the review's background says.
A proposed mechanism does not show that the effect happens in people.
People with a history of skin cancer can ask their doctor about sun protection; the studies do not tell anyone to avoid grapefruit.
Kidney stones (grapefruit juice)
Mixed findingsResults are mixed. Three large studies of eating habits linked grapefruit juice with more kidney stones, while ten small clinical studies found citrus juices raised urine citrate, which is usually thought protective. Grapefruit and orange juice also raised urine oxalate.
1 studiesJuice, not the whole fruit.
Studies, doses and limits
What the trials found
A 2021 systematic review of 13 articles on orange, grapefruit and lemon juice and kidney stones.
Results
Large studies: grapefruit juice a risk factor. Small clinical studies: raised urine citrate and, for grapefruit and orange, oxalate. The authors say more data are needed before any recommendation.
Effect sizes as reported
Qualitative; no pooled figures in the abstract.
Why this rating
Large and small studies point in different directions, and the abstract gives no numbers.
Form and dose studied
Juice, not the whole fruit.
Who was studied
Adults in observational and small clinical studies.
Limits
Juice only; mixed findings.
Why researchers looked
Citrus juices change the chemistry of urine, which matters for stone formation.
Proposed mechanism Human measurement
Citrus juices change urine citrate, acidity and oxalate (measured in small studies).
A proposed mechanism does not show that the effect happens in people.
People who have had kidney stones can ask their clinician about grapefruit juice.
Connections to the rest of health
How Grapefruit connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Healthy Weight | Low certainty | Body weight (grapefruit products in overweight adults): In three short trials of grapefruit products in 250 overweight or obese adults, body weight did not differ significantly from the control groups. The average difference was under half a kilogram and the range included no change. | 6 | |
| Heart Health | Potential benefit | Very low certainty | Blood pressure (grapefruit products in overweight adults): The same trials found a very small fall in the top blood pressure number. The change was only about 2 mmHg and its range only just stayed below zero. The authors say they cannot draw firm conclusions. | 6 9 |
| Immune Wellness | Moderate certainty | Vitamin C supply and scurvy (deficiency): Grapefruit is one of the citrus fruits listed among the best food sources of vitamin C. Severe vitamin C deficiency causes scurvy, which mainly affects older, malnourished adults. Eating vitamin C-rich foods meets the need; there is no sign of extra benefit beyond that. | 13 15 | |
| Immune Wellness | Low certainty | Colds (vitamin C from food or supplements): MedlinePlus says that for most people vitamin C supplements or vitamin C-rich foods do not lower the chance of catching a cold. People who take vitamin C supplements regularly might have slightly shorter or milder colds. | 13 | |
| Cancer Support | Potential benefit | Very low certainty | Oesophageal (food-pipe) cancer risk (citrus fruit in the diet): In a pooled analysis of mostly case-control studies, people who ate more citrus fruit had a lower risk of the squamous cell type of oesophageal cancer, but not of adenocarcinoma. This is a link seen in eating habits, and grapefruit is not separated from other citrus. | 8 |
| Skin Health | Very low certainty | Skin cancer risk (citrus in the diet): a possible harm signal: In a large European study, people who ate the most citrus had a slightly higher chance of skin cancer than those who ate the least. A review of dietary furocoumarins, sun-sensitising plant compounds found in citrus, rated the evidence for a melanoma link as moderate but could not say how much intake matters. These are links, not proof that grapefruit causes skin cancer. | 5 4 | |
| Kidney Urinary | Mixed findings | Kidney stones (grapefruit juice): Results are mixed. Three large studies of eating habits linked grapefruit juice with more kidney stones, while ten small clinical studies found citrus juices raised urine citrate, which is usually thought protective. Grapefruit and orange juice also raised urine oxalate. | 1 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Metabolic System | Biological association | Low certainty | Studied for: Body weight (grapefruit products in overweight adults) | 6 |
| Cardiovascular System | Biological association | Very low certainty | Studied for: Blood pressure (grapefruit products in overweight adults) | 6 9 |
| Immune System | Biological association | Moderate certainty | Studied for: Vitamin C supply and scurvy (deficiency) Studied for: Colds (vitamin C from food or supplements) | 13 15 |
| Digestive System | Biological association | Very low certainty | Studied for: Oesophageal (food-pipe) cancer risk (citrus fruit in the diet) | 8 |
| Integumentary System | Biological association | Very low certainty | Studied for: Skin cancer risk (citrus in the diet): a possible harm signal | 5 4 |
| Urinary System | Biological association | Mixed findings | Studied for: Kidney stones (grapefruit juice) | 1 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Food allergy | Adverse effect or risk | Documented risk | Citrus sensitisation is common in people with pollen allergy; severe reactions need emergency care. Citrus sensitisation is common in people with pollen allergy. Preparation or compound: Citrus fruit |
3 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Body weight | Biological association | Low certainty | Measured in trials: no significant change. A lab change is not the same as a health benefit. | 6 |
| Systolic blood pressure | Biological association | Very low certainty | Measured in trials: lowered slightly. A lab change is not the same as a health benefit. | 6 9 |
| Urine citrate | Biological association | Low certainty | Measured in trials: raised in small studies. A lab change is not the same as a health benefit. | 1 |
| Urine oxalate | Biological association | Low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 1 |
K. Biological pathways
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Vitamin C | Biological association | Composition data and reference article | Essential nutrient that prevents scurvy. Preparation or compound: Flesh and juice |
15 13 |
| Dietary fibre | Biological association | Composition data | Provides fibre in the diet. Juice has less fibre than the fruit. Preparation or compound: Flesh |
15 |
| Beta-carotene and lycopene | Biological association | Composition data | No grapefruit trial of these compounds was found in the sources read. Preparation or compound: Flesh (amounts in the USDA item for pink, red and white grapefruit combined) |
15 |
| Furocoumarins | Biological association | Epidemiology and lab background | Make skin more sensitive to sunlight when applied to the skin, and are a suspected reason for the citrus and skin cancer link. | 4 5 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).
Evidence at a glance: what changed in 1 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Grapefruit. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing grapefruit summary, re-read the USDA FoodData Central record, and read PubMed abstracts and the FDA, NHS and MedlinePlus pages. Only abstracts were read for studies. Items we could not verify are flagged in the research gaps.
Study library: every study we checked 15
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Barghouthy 2021 Role of Citrus Fruit Juices in Prevention of Kidney Stone Disease (KSD): A Narrative Review. Nutrients · PMID 34836376 · DOI |
Systematic review (narrative synthesis) |
13 articles: 3 large epidemiological studies and 10 small prospective clinical studies | Orange, grapefruit and lemon juices juice Varied · vs Varied |
Three large epidemiological studies found grapefruit juice was a risk factor for stones. Small clinical studies found grapefruit, orange and lemon juice all raised urine citrate, and grapefruit and orange juice also raised urine oxalate. The authors say more and better data are needed before recommendations can be made. Qualitative; no pooled figures in the abstract (n/a) Methods, limits and fundingOutcomes: Kidney stone risk; urine citrate, pH and oxalate Limitations: Juice, not the whole fruit. Mixed findings between large and small studies. Funding and conflicts: Authors declared no conflicts of interest Read: abstract |
| Chorin 2019 Grapefruit juice prolongs the QT interval of healthy volunteers and patients with long QT syndrome. Heart Rhythm · PMID 31075442 · DOI |
Open label randomised crossover study with blinded outcome assessment |
40 30 healthy volunteers and 10 patients with congenital long QT syndrome |
Grapefruit juice (2 L in divided doses, as given in the trial; not advice); moxifloxacin as a comparison drug juice 2 L in divided doses (trial detail only) Single-day test · vs Off-drug electrocardiograms and moxifloxacin |
Grapefruit juice lengthened the heart's QT interval, by about as much as moxifloxacin in healthy volunteers. The effect was larger in women and in people with long QT syndrome. Net QTc prolongation 14.0 ms (95% CI 6.2-21.7) in healthy volunteers; 21.8 ms (95% CI 3.4-35.3) in long QT patients (6.2-21.7 ms) Methods, limits and fundingOutcomes: QT interval on the electrocardiogram Limitations: Small, open-label, very large amount of juice, juice not whole fruit, short follow-up. A QT change on a tracing does not by itself show harm. Funding and conflicts: Funding and competing interests not stated in the abstract read. Read: abstract |
| Iorio 2013 Citrus allergy from pollen to clinical symptoms. PLoS One · PMID 23308273 · DOI |
Cross sectional clinical and laboratory study |
Children and adults with pollen allergy (pollinosis) | Citrus fruits (skin prick-to-prick testing) fruit |
39% of the people with pollen allergy were sensitised to citrus fruits, and an IgE-mediated allergy was confirmed by prick-to-prick testing in all of them. Lab work suggested citrus allergens resemble those in grasses and apple. 39% sensitised (n/a) Methods, limits and fundingOutcomes: Sensitisation to citrus and cross-reactivity with pollens and fruits Limitations: People already selected for pollen allergy, so this is not the rate in the general public. Sensitisation is not the same as symptoms. Funding and conflicts: Authors declared no competing interests Read: abstract |
| Kaiser 2025 The Impact of Dietary Intake of Furocoumarins and Furocoumarin-Rich Foods on the Risk of Cutaneous Melanoma: A Systematic Review. Nutrients · PMID 40284161 · DOI |
Systematic review (registered with PROSPERO, CRD42023428596) |
20 publications from 19 observational studies | Dietary furocoumarins and furocoumarin-rich foods (grapefruit not named in the abstract) foods · vs Lower intake |
The authors found moderate evidence that higher dietary furocoumarin intake acts as a risk factor for melanoma, but could not say how much intake raises the risk. They did not pool the results because the studies were too different. Qualitative; no pooled figure (n/a) Methods, limits and fundingOutcomes: Melanoma risk Limitations: Observational; methods differ widely; sun exposure data limited. The abstract does not say how much grapefruit contributes. Funding and conflicts: Authors declared no conflicts of interest Read: abstract |
| Mahamat-Saleh 2020 Citrus intake and risk of skin cancer in the European Prospective Investigation into Cancer and Nutrition cohort (EPIC). Eur J Epidemiol · PMID 32710289 · DOI |
Prospective cohort |
270112 270,112 adults in 10 European countries, mean follow-up 13.7 years, 8,448 skin cancers |
Total citrus, citrus fruit and citrus juice from food questionnaires (grapefruit not separated in the abstract) fruit and juice Mean 13.7 years · vs Lowest quarter of intake |
People in the highest quarter of citrus intake had a slightly higher chance of skin cancer than those in the lowest quarter, mainly basal cell and squamous cell cancer. Citrus fruit alone was linked with melanoma. Total citrus, highest vs lowest quarter: HR 1.10 (95% CI 1.03-1.18). Citrus fruit: HR 1.08 (1.01-1.16). Citrus fruit and melanoma: HR 1.23 (1.02-1.48). (1.03-1.18 (total citrus)) Methods, limits and fundingOutcomes: Skin cancer (basal cell, squamous cell, melanoma) Limitations: Observational, so cause is not shown. Food questionnaires at one time point. Sun exposure was not fully captured, which the authors say limits conclusions about furocoumarins. Grapefruit is not separated in the abstract. Funding and conflicts: Funding and competing interests not stated in the abstract read. Read: abstract |
| Onakpoya 2017 The effect of grapefruits (Citrus paradisi) on body weight and cardiovascular risk factors: A systematic review and meta-analysis of randomized clinical trials. Crit Rev Food Sci Nutr · PMID 25880021 · DOI |
Systematic review and meta analysis of randomised trials |
250 3 randomised trials in overweight or obese adults (250 people in total) |
Grapefruit products (the abstract does not say which forms: fruit, juice or capsules) fruit and products Short (not specified in the abstract) · vs Control groups |
Body weight did not differ significantly between grapefruit and control groups. Systolic blood pressure fell slightly. The authors say there were too few trials, they were short, and no minimum effective amount has been set, which limits what can be concluded. The trials were rated moderate quality. Body weight: mean difference -0.45 kg (95% CI -1.06 to 0.16; I2 = 53%). Systolic blood pressure: -2.43 mmHg (95% CI -4.77 to -0.09; I2 = 0%). (-4.77 to -0.09 mmHg (systolic)) Methods, limits and fundingOutcomes: Body weight, blood pressure, blood fats Limitations: Only 3 trials, short, forms of grapefruit not given in the abstract, only overweight or obese adults. Lipid results are not given in the abstract. Funding and conflicts: Funding and competing interests not stated in the abstract read. Read: abstract |
| Siwek 2024 Interactions between grapefruit juice and psychotropic medications: an update of the literature and an original case series. Expert Opin Drug Metab Toxicol · PMID 38721667 · DOI |
Narrative review plus case series of 9 patients |
9 Preclinical and clinical literature to February 2024 plus 9 patients |
Grapefruit juice juice |
The authors say the effect of grapefruit juice on the gut enzyme CYP3A4 appears to be the main route behind most reported interactions with psychiatric medicines. Some cases show this is not the only route, and at times it is not relevant. The risk needs more study in real-world settings. Qualitative (n/a) Methods, limits and fundingOutcomes: Interactions between grapefruit juice and medicines for mental health Limitations: Review of mixed-quality reports and a small case series; juice only. Funding and conflicts: Funding and competing interests not stated in the abstract read. Read: abstract |
| Zhao 2018 Intakes of citrus fruit and risk of esophageal cancer: A meta-analysis. Medicine (Baltimore) · PMID 29595629 · DOI |
Meta analysis of observational studies (20 case control, 5 cohort) |
25 articles with 5,730 people who had oesophageal cancer | Citrus fruit eaten in the usual diet (grapefruit not separated) fruit · vs Lower intake |
Higher citrus fruit intake went with a lower risk of oesophageal cancer overall and of the squamous cell type. There was no clear link with adenocarcinoma. All oesophageal cancer: RR 0.65 (95% CI 0.56-0.75). Squamous cell: RR 0.59 (0.47-0.76). Adenocarcinoma: RR 0.86 (0.74-1.01). (0.56-0.75 (overall)) Methods, limits and fundingOutcomes: Oesophageal cancer risk, by type Limitations: Mostly case-control studies, which are weak for cause. Citrus fruit of all kinds is grouped together, so grapefruit alone is not shown. Heterogeneity moderate (I2 51-61%). Funding and conflicts: Authors declared no conflicts of interest Read: abstract |
| s-fda-grapefruit-drugs FDA: Grapefruit Juice and Some Drugs Don't Mix · Source |
Official consumer guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-fda-produce-safely FDA: Selecting and Serving Produce Safely · Source |
Official consumer guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-gbif-citrus-paradisi GBIF Backbone: Citrus x paradisi Macfad. (usageKey 7469645) · Source |
Reference database n/a |
Methods, limits and fundingRead: full-text | ||
| s-medlineplus-potassium MedlinePlus: Potassium in diet · Source |
Reference encyclopaedia article n/a |
Methods, limits and fundingRead: full-text | ||
| s-medlineplus-vitamin-c MedlinePlus: Vitamin C · Source |
Reference encyclopaedia article n/a |
Methods, limits and fundingRead: full-text | ||
| s-nhs-simvastatin NHS: Simvastatin · Source |
Official medicine guidance n/a |
Methods, limits and fundingRead: full-text | ||
| s-usda-fdc-173033 USDA FoodData Central: Grapefruit, raw, pink and red and white, all areas (FDC 173033, SR Legacy) · Source |
Food composition database n/a |
Methods, limits and fundingRead: full-text |
What we do not know yet
- No trial has tested eating plain grapefruit for weight, blood pressure, cholesterol or blood sugar; the trials we read did not say which forms they used.
- The cancer studies group grapefruit with other citrus, so a grapefruit-only effect is not known.
- Pregnancy, breastfeeding, children, pesticide residues, reflux and tooth effects were not researched.
- The FDA gives no safe amount or timing for grapefruit with medicines, and this page gives none.
- Seed, peel and capsule products were not covered.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue before the page changes.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 4
Body weight
No significant change in trials
The body's weight in kilograms.
Low certaintyResults and what it means
Why it was measured
A simple measure of weight change in trials.
Statistical vs. clinical meaning
No clear effect found.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 6 | -0.45 kg (95% CI -1.06 to 0.16), not significant | 250 overweight or obese adults in 3 trials | Grapefruit products, forms not specified in the abstract |
Systolic blood pressure
Lowered slightly in trials
The higher number in a blood pressure reading, taken when the heart beats.
Very low certaintyResults and what it means
Why it was measured
A standard marker of heart and blood-vessel risk.
Statistical vs. clinical meaning
A very small change from few short trials.
Safety implication
Grapefruit can interact with some blood pressure medicines.
| Study | Result | People | Product |
|---|---|---|---|
| 6 | -2.43 mmHg (95% CI -4.77 to -0.09) | Overweight or obese adults in 3 trials | Grapefruit products, forms not specified in the abstract |
Urine citrate
Raised in small studies in trials
A substance in urine that helps stop stones forming.
Low certaintyResults and what it means
Why it was measured
Used in kidney stone research.
Statistical vs. clinical meaning
Small studies of juice only.
Safety implication
Large population studies point the other way for grapefruit juice.
| Study | Result | People | Product |
|---|---|---|---|
| 1 | Orange, grapefruit and lemon juice all increased urinary citrate in small prospective clinical studies | Participants in 10 small clinical studies | Citrus juices |
Urine oxalate
Raised in trials
A substance in urine that can form some kinds of kidney stone.
Low certaintyResults and what it means
Why it was measured
Used in kidney stone research.
Statistical vs. clinical meaning
Small studies of juice only.
Safety implication
Relevant to people who form stones.
| Study | Result | People | Product |
|---|---|---|---|
| 1 | Orange and grapefruit juices significantly increased urinary oxalate | Participants in small clinical studies | Orange and grapefruit juice |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 4
- Grapefruit can change how some medicines work: ask a pharmacist first. The US FDA says grapefruit juice and grapefruit can affect medicines. Grapefruit juice can block a gut enzyme called CYP3A4 that breaks down many medicines, so more of the medicine can enter the blood and side effects can increase. The FDA's examples include some statins (simvastatin, atorvastatin), nifedipine for blood pressure, cyclosporine for organ transplants, buspirone for anxiety, budesonide for bowel disease and amiodarone for heart rhythm. It does not affect every medicine in these groups, and the effect depends on the person, the drug and the amount. The NHS tells people taking simvastatin to avoid grapefruit juice. If you take any regular medicine, check with a pharmacist. Authoritative guidance 9 14 7
- It can also make a medicine work less. For the antihistamine fexofenadine (Allegra), the FDA says grapefruit juice can mean less medicine enters the blood, so it may work less well. This happens through drug transporters rather than the enzyme. Authoritative guidance 9
- Other fruit may act the same way. The FDA says Seville oranges (often used in marmalade), pomelos and tangelos might have the same effect as grapefruit juice, and advises not eating those fruits if your medicine interacts with grapefruit juice. Authoritative guidance 9
- Allergy to citrus exists. In a study of people with pollen allergy, 39% were sensitised to citrus fruits, and lab work suggested citrus allergens resemble those in grasses and apple. Sensitisation is not the same as symptoms, and the group was already allergic to pollen. A serious allergic reaction is an emergency. Human observational 3
Side effects 4
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Higher blood levels of some medicines and more side effects of those medicines The FDA says the severity differs between people, drugs and amounts of juice. | Not established | mild to severe, depending on the medicine Depends on the medicine; the FDA says too much drug in the blood may cause more side effects, and for some statins a higher risk of liver and muscle damage that can lead to kidney failure. | Authoritative guidance 9 |
| Lengthening of the heart's QT interval after a very large amount of juice In a trial of 30 healthy volunteers and 10 people with congenital long QT syndrome, 2 L of grapefruit juice lengthened QTc by 14.0 ms in healthy volunteers (95% CI 6.2-21.7) and by 21.8 ms in those with long QT syndrome (95% CI 3.4-35.3). The amount was far above a normal serving; this is a trial detail, not advice. The effect was larger in women. | Not established | measured on an electrocardiogram; clinical harm not shown in the abstract Not stated in the abstract. | Randomised crossover trial 2 |
| Allergic reaction to citrus Sensitisation does not always mean symptoms. | 39% of people with pollen allergy were sensitised in one study (not the general public) | mild to severe Varies; severe reactions need emergency care. | Human observational 3 |
| Foodborne illness from unwashed or poorly handled fruit FDA says harmful bacteria can contaminate produce in the field or after harvest. | Not established | mild to severe Varies | Authoritative guidance 10 |
Liver
No liver injury from eating grapefruit was found in the sources read. The FDA does say that, with some statins, grapefruit juice can raise the amount of medicine in the body and increase the risk of liver and muscle damage. LiverTox was not checked. 9
How often. No frequency found.
Monitoring. For people on statins or other affected medicines, ask your prescriber or pharmacist.
This is a safety connection. It is not evidence that Grapefruit supports liver health.
Medicines and supplements 7
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Some statins (for example simvastatin and atorvastatin) prescription | Grapefruit juice blocks the intestinal enzyme CYP3A4 that helps break the medicine down, so more enters the blood. | The FDA says this may raise the risk of liver and muscle damage that can lead to kidney failure. The NHS tells people on simvastatin to avoid grapefruit juice. | Authoritative guidance High certainty 9 14 | Ask your pharmacist about your own statin. |
| Some blood pressure medicines (nifedipine is the FDA's example) prescription | CYP3A4 blocking, so more medicine enters the blood. | More side effects are possible. The FDA does not say every blood pressure medicine is affected. | Authoritative guidance High certainty 9 | Ask your pharmacist. |
| Transplant (cyclosporine), anti-anxiety (buspirone), bowel (budesonide) and heart-rhythm (amiodarone) medicines prescription | CYP3A4 blocking, so more medicine enters the blood. | The FDA lists these as examples of drug types that grapefruit juice can interact with; it does not affect all drugs in these groups. | Authoritative guidance High certainty 9 | Ask your pharmacist. |
| Medicines for mental health prescription | The CYP3A4 effect explains most reported interactions, but a review and case series say it does not explain all of them. | A 2024 review says the risk needs more study in real-world settings. | Narrative review and case series Low certainty 7 | Ask your prescriber or pharmacist. |
| Medicines that lengthen the QT interval, and people with long QT syndrome prescription | Not established in the abstract. | A small trial found a very large amount of juice lengthened the QT interval on its own, more so in women and in long QT syndrome. The trial does not show what ordinary servings do, and it does not test combinations with medicines. | Randomised crossover trial Low certainty 2 | If you have long QT syndrome or take a heart-rhythm medicine, ask your doctor. |
| Fexofenadine (Allegra) antihistamine prescription and over the counter | Grapefruit juice affects drug transporters, so less medicine enters the blood. | The medicine may not work as well. The FDA notes the label says not to take it with fruit juices. | Authoritative guidance High certainty 9 | Check the label or ask a pharmacist. |
| ACE inhibitors, ARBs and potassium-sparing diuretics (potassium in citrus) prescription | These medicines can raise blood potassium; citrus fruits contain potassium. | MedlinePlus lists these medicines as common causes of high blood potassium and lists citrus among potassium-rich fruits. It does not give a grapefruit-specific warning. A cup of sections has about 320 mg of potassium (calculated from USDA). | Reference article Low certainty 12 15 | If you were told to watch potassium, ask your clinician. |
Who should check first 3
| Situation | Advice | Evidence |
|---|---|---|
| Taking a medicine whose label or pharmacist says to avoid grapefruit | Follow the label and your pharmacist. The FDA says to check fruit juices and juice drinks for grapefruit juice too. | Authoritative guidance 9 |
| Known citrus allergy with swelling or trouble breathing | Avoid it and get an allergy assessment. Follow your own emergency plan. | Human observational 3 |
| Kidney problems or told to limit potassium | MedlinePlus says people with kidney problems, particularly on dialysis, should not eat too many potassium-rich foods. Ask your clinician about citrus. | Reference article 12 |
Overdose, product quality and regulators
Summary. Grapefruit flesh is an ordinary food. The sources read describe medicine interactions, not poisoning from the fruit.
Animal. Not reviewed.
Human doses studied. A trial gave 2 L of juice for QT testing (trial detail, not advice).
High dose or long term signals. Large studies of eating habits link citrus with slightly higher skin cancer risk, and grapefruit juice with kidney stones in some studies. These are associations.
Overdose response. Not found.
Genotoxicity. Not reviewed.
Toxic or hazardous parts. Not assessed. Seed and peel extracts were not covered by the sources read.
Like any raw produce, grapefruit can carry bacteria on the peel. Pesticide residues and metals in grapefruit were not looked up.
Bacteria on produce. FDA says to wash produce under running water, even if you will peel it, without soap or produce wash. Washing reduces bacteria but does not eliminate them. Refrigerate pre-cut produce at 40 F (about 4 C) or below. 10
| Body | Action | Date |
|---|---|---|
| FDA (US Food and Drug Administration) (United States) | Consumer update: grapefruit juice and grapefruit can interact with some medicines; some labels carry warnings source | 2021-07-01 (content current as of) |
| NHS (UK) (United Kingdom) | Says to avoid grapefruit juice with simvastatin source | 2026-10-25 (page read) |
| FDA (United States) | Consumer advice on washing and storing fresh produce source | 2026-10-25 (page read) |
When to get medical help
- Swelling of the lips, face, tongue or throat after eating grapefruit
- Trouble breathing, wheezing or a tight throat
- Feeling faint, dizzy or collapsing after eating
- Fainting, a racing or irregular heartbeat if you take a heart-rhythm medicine or have long QT syndrome
- Unusual muscle pain or weakness, or dark urine, if you take a statin (general medical caution; the FDA names liver and muscle damage as a risk but the page read does not list symptoms)
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is grapefruit good for?
Can grapefruit affect my medicines?
Yes. The FDA says grapefruit juice and grapefruit can raise the blood level of some statins, blood pressure, transplant, anti-anxiety, bowel and heart-rhythm medicines. It does not affect every medicine in those groups. Ask a pharmacist.
Is grapefruit safe with statins?
Does grapefruit help with weight loss?
Not on the evidence read. Three short trials in 250 overweight or obese adults found no significant difference in body weight (-0.45 kg, range -1.06 to 0.16).
Does grapefruit lower blood pressure?
How much vitamin C is in a grapefruit?
USDA lists 34.4 mg per 100 g of raw grapefruit, which is about 79 mg in a cup of sections and about 44 mg in half a medium grapefruit.
Does grapefruit prevent colds?
MedlinePlus says vitamin C supplements or vitamin C-rich foods do not lower the chance of catching a cold for most people. This is not a grapefruit-specific trial.
Does grapefruit affect cancer risk?
Is grapefruit juice bad for kidney stones?
Results are mixed. Three large studies linked grapefruit juice with more stones, while small studies found citrus juices raised urine citrate. People who have had stones can ask their clinician.
Can I be allergic to grapefruit?
Yes. In one study of people with pollen allergy, 39% were sensitised to citrus fruits. Swelling of the face or throat or trouble breathing is an emergency: call 911 (999 in the UK).
Do other fruits act like grapefruit with medicines?
The FDA says Seville oranges, pomelos and tangelos might have the same effect as grapefruit juice, and advises not eating them if your medicine interacts with grapefruit juice.
Is grapefruit safe in pregnancy?
We did not find a source on grapefruit as a food in pregnancy or breastfeeding. A doctor or midwife can advise, and a pharmacist can check your own medicines.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-25
- Last substantive update
- 2026-10-25
- How we research
- We started from our existing grapefruit summary, re-read the USDA FoodData Central record, and read PubMed abstracts and the FDA, NHS and MedlinePlus pages. Only abstracts were read for studies. Items we could not verify are flagged in the research gaps.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown.
Sources 15
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Barghouthy Y, Somani BK. Role of Citrus Fruit Juices in Prevention of Kidney Stone Disease (KSD): A Narrative Review.. Nutrients. 2021. PMID 34836376. DOI 10.3390/nu13114117. (abstract)
- Chorin E, Hochstadt A, Granot Y, et al.. Grapefruit juice prolongs the QT interval of healthy volunteers and patients with long QT syndrome.. Heart Rhythm. 2019. PMID 31075442. DOI 10.1016/j.hrthm.2019.04.039. (abstract)
- Iorio RA, Del Duca S, Calamelli E, et al.. Citrus allergy from pollen to clinical symptoms.. PLoS One. 2013. PMID 23308273. DOI 10.1371/journal.pone.0053680. (abstract)
- Kaiser I, Rappl A, Bolay LS, et al.. The Impact of Dietary Intake of Furocoumarins and Furocoumarin-Rich Foods on the Risk of Cutaneous Melanoma: A Systematic Review.. Nutrients. 2025. PMID 40284161. DOI 10.3390/nu17081296. (abstract)
- Mahamat-Saleh Y, Cervenka I, Al-Rahmoun M, et al.. Citrus intake and risk of skin cancer in the European Prospective Investigation into Cancer and Nutrition cohort (EPIC).. Eur J Epidemiol. 2020. PMID 32710289. DOI 10.1007/s10654-020-00666-9. (abstract)
- 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.. Crit Rev Food Sci Nutr. 2017. PMID 25880021. DOI 10.1080/10408398.2014.901292. (abstract)
- Siwek M, Krupa AJ, Woroń J. Interactions between grapefruit juice and psychotropic medications: an update of the literature and an original case series.. Expert Opin Drug Metab Toxicol. 2024. PMID 38721667. DOI 10.1080/17425255.2024.2352468. (abstract)
- Zhao W, Liu L, Xu S. Intakes of citrus fruit and risk of esophageal cancer: A meta-analysis.. Medicine (Baltimore). 2018. PMID 29595629. DOI 10.1097/MD.0000000000010018. (abstract)
- . FDA: Grapefruit Juice and Some Drugs Don't Mix. . . (full-text)
- . FDA: Selecting and Serving Produce Safely. . . (full-text)
- . GBIF Backbone: Citrus x paradisi Macfad. (usageKey 7469645). . . (full-text)
- . MedlinePlus: Potassium in diet. . . (full-text)
- . MedlinePlus: Vitamin C. . . (full-text)
- . NHS: Simvastatin. . . (full-text)
- . USDA FoodData Central: Grapefruit, raw, pink and red and white, all areas (FDC 173033, SR Legacy). . . (full-text)
Where to buy
Check the label first. Whatever you buy, look for these:
- Unsweetened with no added sugar, if you want the fruit alone
- Sulfur dioxide (sulfites) listed on the label: some people react
- A best-by date and a resealable bag
- Dried fruit is high in sugar and calories, so watch portions
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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