A Surprising Result From the Peppermint Aisle: Blood Pressure and a Common Kitchen Herb
- Joyce Knieff, ND, LAc
- Jun 8
- 7 min read
If you've ever been told you have prehypertension or stage 1 hypertension, you probably know the feeling that follows. The numbers aren't quite bad enough to start medication. They aren't quite good enough to ignore. You leave the appointment with a vague directive to lose some weight, walk more, eat less salt, and recheck in three months. For a lot of people, that middle zone is where blood pressure drifts in the wrong direction. A small trial out of the United Kingdom, just published in PLOS ONE, adds something interesting to that picture. The intervention is twice-daily peppermint oil. The result is meaningful.
TL;DR: A small UK trial found that twice-daily peppermint oil lowered systolic blood pressure by about 8.5 mmHg over 20 days, though it's early, single-site work.
Key takeaways:
A 40-person randomized trial tested 100 microliters of peppermint oil daily for 20 days.
Systolic pressure fell from 130 to 122 mmHg; the placebo group didn't budge.
The trial is small and short, so it isn't the last word.
Peppermint oil isn't the same as peppermint tea, candies, or topical products.
What the research found
The study, led by Jonathan Sinclair at the University of Lancashire, was a 20-day, parallel, randomized, placebo-controlled trial of 40 adults with pre- and stage 1 hypertension. Participants were assigned to either 100 microliters per day of peppermint essential oil (about a third of a small dropper, split into two doses) or a peppermint-flavored placebo. Neither participants nor researchers knew who was getting which until the trial ended.
The primary outcome was systolic blood pressure (the top number) at 20 days. In the peppermint arm, the average systolic pressure dropped from 130 mmHg at baseline to 122 mmHg at the end of the study. In the placebo arm, it didn't change at all (131 to 131 mmHg). The adjusted between-group difference was about 8.5 mmHg lower in the peppermint group, with a 95 percent confidence interval ranging from roughly 3 to 14 mmHg. The effect size was large by clinical-trial standards. Compliance with the protocol was 93 percent in the peppermint arm, only one mild adverse event was reported, and one participant was lost to follow-up.
A few honest caveats. The trial is small. The follow-up was only 20 days, which doesn't tell us what happens at 6 or 12 months. The cohort was a single research center, not a multi-site replication. The result is striking enough to take seriously and small enough that it shouldn't be the last word. The same research team has a published protocol for the trial in PLOS ONE and references an earlier pilot in healthy volunteers, so this is part of a planned line of work rather than a one-off finding.
Where this fits in the broader picture
Blood pressure responds to a lot of inputs, and the strongest evidence base sits on the dietary and lifestyle side. A 2021 systematic review and meta-analysis in Advances in Nutrition looked at the ratio of sodium to potassium in the diet across 39 studies and found that shifting that ratio (less sodium, more potassium from foods like leafy greens, beans, sweet potatoes, and bananas) was associated with measurable reductions in both systolic and diastolic pressure. A 2025 meta-analysis in Nutrition, Metabolism and Cardiovascular Diseases compared two versions of the Mediterranean diet and found that the mixed-nuts version produced lower systolic pressure than the olive-oil version, both within an eating pattern that already supports cardiovascular health. The point is that food does most of the heavy lifting here. Peppermint oil, if the new trial replicates, would be one tool added to a foundation that diet and movement have already laid.
The proposed mechanism for peppermint involves menthol, the major active compound in the essential oil. Menthol activates a class of receptors called TRP channels that play a role in vascular tone. Peppermint also contains flavonoids that have antioxidant and mild anti-inflammatory effects. Whether those mechanisms fully explain the blood-pressure shift in the Sinclair trial isn't settled. The mechanistic picture is plausible. It isn't proven.
The naturopathic perspective
The reason this finding is worth paying attention to isn't that peppermint oil is some kind of breakthrough. It's that prehypertension and stage 1 hypertension occupy a stretch of the cardiovascular timeline where lifestyle, food, sleep, and stress can still meaningfully shift the trajectory before medication becomes the only option left. The body in that stage isn't broken. It is responding to inputs. The question is whether those inputs can be adjusted.
Whole-person care in this stage has always taken the inputs seriously. Sleep, because blood pressure tracks with sleep quality and sleep duration in ways that show up within weeks. Movement, because regular aerobic and resistance exercise lower resting pressure independently of weight loss. Stress, because chronic sympathetic activation drives both peripheral vascular tone and salt retention. The eating pattern, because sodium-to-potassium ratio, fiber, polyphenols, and omega-3 intake all show up in the blood pressure picture. Body composition, because visceral adiposity drives insulin resistance and downstream vascular changes. And the question of what underlying systems (thyroid, kidneys, adrenal function, sleep apnea) might be contributing to numbers that aren't responding to the basics.
Within that frame, peppermint oil at the studied dose sits as an interesting addition rather than a stand-alone strategy. It's also worth noting that essential oils are not interchangeable with peppermint tea, peppermint candies, or topical peppermint products. The Sinclair trial used a specific oral preparation at a specific dose, and the results don't automatically transfer to other forms. Anyone considering peppermint oil supplementation should know that it can interact with certain medications (especially those affecting GERD, since peppermint relaxes the lower esophageal sphincter), is not recommended in significant doses during pregnancy, and isn't appropriate for young children. A clinician who knows your full picture is the right person to bring this kind of question to.
How to apply this now
The honest practical message isn't "buy peppermint oil." It's closer to: if your numbers are in the prehypertension or stage 1 range, the foundational work matters, and there is more leverage than most clinical visits make time to discuss. The DASH-style eating pattern (plenty of vegetables and fruit, beans and legumes, nuts and seeds, whole grains, fatty fish, with limited ultra-processed food and added salt). Regular movement that includes both aerobic and resistance work. Sleep that actually restores. Stress practices that downshift the nervous system in real ways, not just on paper. A clinician who can look at the full picture, including any underlying drivers, and help you decide what to add and when.
If peppermint oil is something you're curious about adding, please have that conversation with a clinician who knows your medications, history, and the dose used in the published research. The Sinclair trial is one piece of an evolving picture, not a prescription.
Frequently asked questions
Should I start taking peppermint oil for my blood pressure?
Not on your own. This was one small, 20-day trial, and it isn't a reason to skip the foundational work or your usual care. If you're curious, bring it to a clinician who knows your medications and history, since peppermint oil can interact with some of them.
How much did the study actually use?
100 microliters of peppermint essential oil per day, split into two doses. That's about a third of a small dropper. The dose matters, and it doesn't transfer to peppermint tea, candies, or topical products.
Who should be careful with peppermint oil?
Anyone with reflux or GERD, since peppermint relaxes the lower esophageal sphincter and can make symptoms worse. It also isn't recommended in significant doses during pregnancy, and it isn't appropriate for young children. Because it interacts with certain medications, a clinician conversation comes first.
If I'm in the borderline range, what moves the numbers most?
Food and lifestyle do most of the heavy lifting. A DASH-style eating pattern, regular movement that includes both aerobic and resistance work, sleep that actually restores, and real stress downshifting all show up in the blood-pressure picture. Peppermint oil, if it holds up, would sit on top of that foundation rather than replace it.
References
Sinclair J, Sant B, Du X, Shadwell G, Dillon S, Butters B, Bottoms L. Effects of peppermint (Mentha x piperita L.) oil on cardiometabolic outcomes in patients with pre- and stage 1 hypertension: A placebo randomized controlled trial. PLoS One. 2026;21(4):e0344538. PMID: 42024666. DOI. Original AANP digest link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0344538
Sinclair J, Du X, Shadwell G, Dillon S, Butters B, Bottoms L. Effects of peppermint (Mentha piperita L.) oil in cardiometabolic outcomes in participants with pre and stage 1 hypertension: Protocol for a placebo randomized controlled trial. PLoS One. 2025;20(5):e0321986. PMID: 40333716. DOI.
Ndanuko RN, Ibrahim R, Hapsari RA, Neale EP, Raubenheimer D, Charlton KE. Association between the Urinary Sodium to Potassium Ratio and Blood Pressure in Adults: A Systematic Review and Meta-Analysis. Adv Nutr. 2021;12(5):1751-1767. PMID: 34117485. DOI.
Pourrajab B, Mirdar Harijani A, Asghari P, Shidfar F. Effect of the Mediterranean diet supplemented with olive oil versus the Mediterranean diet supplemented with mixed nuts on blood pressure and serum lipid indexes among adults: a systematic review and meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis. 2025;35(11):104166. PMID: 40651889. DOI.
A note before you go
This is for educational purposes and is not a substitute for individualized medical care. If you have been told your blood pressure is elevated, please work with a clinician who can review your full picture, including medications, family history, and any underlying contributors. Essential oil supplementation interacts with medications and conditions in ways that warrant a real clinical conversation.
Related reading
Reviewed by Joyce Knieff, ND, LAc on 2026-06-08.
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The post is about the borderline range where the foundational work can still move your numbers between office visits. A validated upper-arm monitor lets you watch how those numbers respond at home, instead of waiting three months for a single reading.
The DASH and Mediterranean eating patterns are the part of this picture with the strongest evidence behind them. A recipe collection built around both can make the day-to-day cooking feel less abstract than a list of guidelines.
If this resonates with what you're experiencing and you'd like to explore a naturopathic approach, book a consultation with our clinic.
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