Does Passion Fruit Lower Blood Pressure?

Passion fruit contains several compounds that have lowered blood pressure in both animal experiments and a handful of small human trials, but the evidence is too thin to call it a proven remedy. The most striking results come from concentrated extracts of the peel and seeds rather than from simply drinking the juice, and the human studies so far involve small groups tracked over just a few weeks. Still, the early findings are genuinely interesting, and the mechanisms behind them are well-characterized enough to explain why researchers keep investigating.

What the Human Studies Actually Found

Two human trials stand out. In one, hypertensive adults took 400 milligrams per day of purple passion fruit peel extract or a placebo for four weeks. Those who received the extract saw their systolic blood pressure drop by about 31 mmHg and their diastolic pressure drop by about 25 mmHg compared to the placebo group, with no reported side effects.¹ Those are large numbers, on par with what you would expect from prescription blood pressure medication. The researchers proposed that the effect was partly driven by the extract’s influence on nitric oxide, a molecule that relaxes blood vessels.

A separate trial focused on piceatannol, a polyphenol concentrated in passion fruit seeds. Overweight men who took piceatannol supplements for eight weeks saw their systolic blood pressure fall from about 131 to 121 mmHg and their diastolic pressure fall from roughly 86 to 77 mmHg, while the placebo group showed no change.² The catch: this effect was limited to overweight men. Non-overweight men, non-overweight women, and overweight women in the same trial did not see a significant change. That kind of subgroup-specific result can be a real biological signal, but it can also be a statistical artifact in a small study. Without replication in a larger group, it is hard to know which.

Then there is the study that found nothing. When researchers gave healthy young adults a single serving of passion fruit juice and tracked their heart rate and blood pressure over the next few hours, there was no meaningful difference compared to placebo.³ This null result matters, because it tells you something about what passion fruit can and cannot do in everyday use.

Why Juice Didn’t Move the Needle

The null result from the juice study is not really a contradiction of the positive findings. It reflects three important differences. First, the subjects were healthy and had normal blood pressure to begin with. Blood-pressure-lowering effects tend to be much more pronounced in people who start with elevated readings; if your vessels are already relaxed and your pressure is already in a healthy range, there is less room for improvement. Second, the study measured acute effects over just a few hours. The positive human trials used daily supplementation over weeks, which gives biologically active compounds time to influence enzyme expression and vascular tone. Third, and probably most important, a glass of juice is not the same as a concentrated extract of the peel or seeds.

The compounds that appear most responsible for blood pressure effects are concentrated in the parts of the fruit you do not typically eat. The peel is rich in polyphenols, and the seeds contain the bulk of the piceatannol. Commercial passion fruit juice is mostly pulp with the seeds strained out, and the peel discarded entirely. So a glass of juice delivers sugar, some potassium, and vitamin C, but very little of the specific compounds that drove the results in the positive trials.

Which Part of the Fruit Contains What

Passion fruit research consistently finds that different parts of the fruit carry different bioactive compounds, and these compounds appear to lower blood pressure through different pathways. Lumping them together as “passion fruit” obscures real differences in how each component works.

Peel (rind): Contains polyphenols like luteolin, GABA (gamma-aminobutyric acid), edulic acid, and anthocyanins. In hypertensive rats, a methanol extract of the rind significantly lowered systolic blood pressure at doses as low as 10 mg per kilogram of body weight.⁴ The researchers attributed this largely to GABA, though a later study using direct blood pressure measurement challenged that, finding that edulic acid and anthocyanin fractions were the active players, while GABA alone did not lower blood pressure and actually increased heart rate.⁵
Seeds: Rich in piceatannol, a stilbene related to resveratrol. This is the compound that lowered blood pressure in overweight men in the eight-week trial. Lab studies show it boosts expression of the enzyme that produces nitric oxide in blood vessel cells, and it does so more effectively than resveratrol.⁶ Seed extracts have also shown the strongest ability to inhibit angiotensin-converting enzyme in lab assays, a mechanism shared by widely prescribed blood pressure drugs.⁷
Pulp: The part you actually eat. Studies in hypertensive rats found that high doses of yellow passion fruit pulp reduced systolic blood pressure, likely through antioxidant activity rather than the direct vascular mechanisms seen with peel and seed extracts.⁸ The doses used were quite large relative to what a person would eat in a serving, though.

The practical upshot is that eating the fruit’s flesh gives you the least potent form of whatever blood-pressure-lowering activity passion fruit offers. The most active compounds sit in the parts you normally throw away.

How These Compounds Might Lower Blood Pressure

At least three distinct mechanisms have been identified in lab and animal research, which is part of why passion fruit keeps attracting attention from researchers. A fruit that only worked through one minor pathway would be less interesting. Multiple pathways acting together could, in theory, produce meaningful effects.

The first mechanism involves nitric oxide. Your blood vessels relax when endothelial cells lining them produce nitric oxide through an enzyme called eNOS. Piceatannol from passion fruit seeds boosts both the amount and the activity of this enzyme in cultured endothelial cells.⁶ More enzyme means more nitric oxide, which means more relaxed blood vessels and lower pressure. The peel extract trial in hypertensive humans also proposed nitric oxide modulation as the mechanism behind its results.¹

The second mechanism is ACE inhibition. Angiotensin-converting enzyme narrows blood vessels by producing a powerful vasoconstrictor. Blocking it is how an entire class of prescription drugs works. Lab assays show that seed extracts from a particular variety of passion fruit (gulupa, or Passiflora edulis f. edulis) have measurable ACE-inhibitory activity, with a relatively low concentration needed to cut enzyme activity in half.⁷ Whether that activity survives digestion and reaches the bloodstream at meaningful levels is a separate question, and one that lab assays alone cannot answer.

The third mechanism is antioxidant protection. Oxidative stress damages blood vessel walls and reduces the availability of nitric oxide, both of which raise blood pressure over time. The yellow passion fruit pulp study found that the antihypertensive effect was accompanied by increased levels of the antioxidant glutathione and decreased markers of oxidative damage.⁸ This is a slower, more indirect route to lower blood pressure than the first two, but it could matter over weeks or months of regular consumption.

The Bioavailability Problem

One of the biggest unsettled questions is whether the compounds that look promising in lab dishes and rat studies actually get absorbed well enough in humans to matter. Piceatannol is a good example of the challenge. Like many polyphenols, it gets rapidly metabolized and cleared from the body. Rat studies show that pairing piceatannol with a cyclodextrin complex substantially increases its absorption in the small intestine and raises the peak levels of both intact piceatannol and its active metabolites in the blood.⁹ That kind of formulation trick is useful in a supplement, but it tells you that raw piceatannol from chewing passion fruit seeds is probably not absorbed very efficiently on its own.

This is a recurring pattern in plant-compound research. A substance does remarkable things to cells in a petri dish, looks good when injected directly into rats, and then disappoints when given orally because the gut breaks it down before it reaches the bloodstream. The positive human trials used either a concentrated peel extract or a purified piceatannol supplement, not fresh fruit. That distinction is critical for anyone hoping to eat their way to lower blood pressure.

Purple Versus Yellow Varieties

Passion fruit comes in two main commercial varieties. The purple type (Passiflora edulis Sims) is smaller, sweeter, and common in subtropical regions. The yellow type (Passiflora edulis Sims f. flavicarpa) is larger, more acidic, and widely grown in tropical areas like Brazil. Most of the blood-pressure research does not specify clearly which variety was used, or uses one without comparing it to the other, so drawing firm conclusions about variety-specific effects is difficult.

The peel extract human trial and several of the rat studies used purple passion fruit, while the pulp antioxidant study specifically used yellow passion fruit pulp.⁸ Purple varieties tend to have higher anthocyanin content in their peels, which contributes to both their color and their polyphenol profile. Yellow varieties have thicker rinds and different proportions of flavonoids. The ACE-inhibition work used gulupa, a distinct species in the same genus, which adds yet another source of variation.⁷ If you are buying passion fruit at a grocery store, you are probably getting whichever variety is locally available, and the research cannot yet tell you that one is meaningfully better than the other for blood pressure.

Potassium and the Basics

Separate from the polyphenol story, passion fruit is a decent source of potassium. A single cup of the raw pulp delivers roughly 700 milligrams, which is about 15 percent of the recommended daily intake for most adults. Potassium’s blood-pressure-lowering effect is well established: it helps your kidneys excrete sodium and relaxes blood vessel walls. This is not unique to passion fruit; bananas, potatoes, and leafy greens deliver potassium too. But it means that even without exotic polyphenol extracts, eating passion fruit regularly as part of a diet rich in fruits and vegetables contributes to the mineral intake pattern associated with healthy blood pressure.

The DASH diet, widely recommended for managing hypertension, emphasizes potassium-rich fruits and vegetables as a central strategy. Passion fruit fits that framework, though no clinical trial has singled it out from other potassium-rich foods for this purpose. If you enjoy passion fruit and eat it regularly, you are likely getting a modest blood pressure benefit from the potassium alone, plus whatever additional effect its polyphenols contribute.

What This Means If You Have High Blood Pressure

The honest read on the current evidence is that passion fruit extracts show genuine biological activity against high blood pressure through multiple pathways, and the handful of human studies are encouraging. But “encouraging” and “proven” are very different things. The human trials involve small numbers of people, short durations, and have not been replicated independently. The dramatic 31 mmHg systolic drop in the peel extract trial, for instance, is an unusually large effect and would benefit from confirmation in a larger, longer study before anyone treats it as a reliable expectation.

If you are currently taking blood pressure medication, do not replace it with passion fruit supplements based on this evidence. If you are interested in trying a passion fruit peel or seed extract as a complementary approach, mention it to your doctor, particularly because the ACE-inhibitory activity identified in seed extracts could theoretically interact with ACE inhibitor medications. Doubling up on the same mechanism, one through a drug and one through a supplement, could push your blood pressure lower than intended.

For people with mildly elevated blood pressure who are not yet on medication, adding passion fruit to an already-good diet is unlikely to hurt and might help. Just keep your expectations realistic: eating the fruit is not the same as taking the concentrated extracts used in the studies, and the research has not established what dose of whole fruit, if any, would produce a clinically meaningful effect.

The GABA Disagreement

One interesting wrinkle in the animal research is a direct contradiction about GABA. The rind of passion fruit contains relatively high concentrations of GABA, and an early rat study attributed much of the peel extract’s blood-pressure-lowering effect to this compound, with polyphenols playing a supporting role.⁴ A later study that used surgically implanted pressure monitors for more accurate measurement tested the individual components separately and found the opposite: GABA alone did not lower any hemodynamic parameter and actually raised heart rate, while edulic acid and the anthocyanin fraction were the true active players.⁵

This kind of reversal is not uncommon in early-stage nutrition research. The first study used indirect blood pressure measurement (essentially a tiny inflatable cuff on the rat’s tail), which is less precise. The follow-up used radiotelemetry, a much more accurate method. The lesson is not just about GABA; it is about how tentative conclusions from small studies can circulate as established facts. You will still find supplements and health blogs crediting GABA from passion fruit with blood-pressure benefits. The better-designed study suggests the credit belongs elsewhere. This is worth keeping in mind whenever any single study’s finding gets promoted as the definitive answer on how a food works.

1
Nutrition Research. Oral administration of purple passion fruit peel extract attenuates blood pressure in female spontaneously hypertensive rats and humans
2
PubMed Central. The Effect of Piceatannol from Passion Fruit (Passiflora edulis) Seeds on Metabolic Health in Humans
3
Preventive Nutrition and Food Science. Acute Effects of Passion Fruit Juice Supplementation on Cardiac Autonomic Function and Blood Glucose in Healthy Subjects
4
Bioscience, Biotechnology, and Biochemistry. Antihypertensive Effect of an Extract of Passiflora edulis Rind in Spontaneously Hypertensive Rats
5
PubMed. Antihypertensive effect of passion fruit peel extract and its major bioactive components following acute supplementation in spontaneously hypertensive rats
6
PubMed. Effect of long-term piceatannol treatment on eNOS levels in cultured endothelial cells
7
Asian Journal of Pharmaceutical and Clinical Research. Potential Uses of the Peel and Seed of Passiflora Edulis F. Edulis Sims Gulupa from Its Chemical Characterization Antioxidant and Antihypertensive Functionalities
8
PubMed. Evaluation of the antihypertensive properties of yellow passion fruit pulp (Passiflora edulis Sims f. flavicarpa Deg.) in spontaneously hypertensive rats
9
PubMed. Administration of Piceatannol Complexed with α-Cyclodextrin Improves Its Absorption in Rats