A small new trial on peppermint oil and blood pressure — what it does and does not tell us
- Joyce Knieff, ND, LAc
- Jun 25
- 6 min read
Patients ask me almost weekly whether there is a natural way to bring blood pressure down without going straight to medication. A new randomized controlled trial in PLoS One looked at exactly that question with peppermint oil, and the numbers got attention online before most clinicians had a chance to read the paper. So let me walk through what the study actually showed, what it does not show, and where it fits in the bigger conversation about prehypertension.
TL;DR: A small 20-day trial found twice-daily peppermint oil lowered systolic blood pressure about 8.5 mmHg versus placebo, but it is far too small and short to change how blood pressure is treated yet.
Key takeaways:
The trial enrolled 40 adults for 20 days, so it is a pilot, not proof.
Systolic pressure fell about 8.5 mmHg versus placebo, with a wide confidence interval.
Peppermint oil can interact with blood pressure and other medications through liver enzymes.
Track your numbers at home and work the lifestyle basics first.
What the research found
The trial, published in April 2026 by a group at the University of Lancashire, enrolled 40 adults with prehypertension or stage 1 hypertension. (Prehypertension is a systolic blood pressure of 120 to 129 mmHg, and stage 1 is 130 to 139 mmHg systolic or 80 to 89 mmHg diastolic, by current American Heart Association definitions.) Participants were randomly assigned to receive either peppermint oil (Mentha x piperita L.) at 100 microliters per day, split into two doses, or a peppermint-flavored placebo. The trial lasted 20 days. It was registered in advance on ClinicalTrials.gov (NCT05561543) and analyzed on an intention-to-treat basis.
At day 20, the peppermint group showed an adjusted systolic blood pressure that was 8.48 mmHg lower than placebo (95% confidence interval -14.24 to -2.73). That is a meaningful effect size for a herbal intervention over three weeks. Compliance was 93 percent in the peppermint arm and there was one adverse event and one dropout in that group.
The authors framed this as preliminary evidence that twice-daily peppermint oil might be a low-cost, well-tolerated option to support blood pressure reduction in this population.
The bigger picture
Forty people for twenty days is a pilot. The investigators say so themselves. A few caveats go with the headline:
A 20-day study cannot tell us anything about durability. Blood pressure has a strong placebo response, a known regression-to-the-mean problem at short follow-up, and substantial day-to-day variability in any single person. A drop at three weeks does not mean the same drop will hold at six months.
The sample is small and the confidence interval is wide. The lower bound of the effect is 2.73 mmHg and the upper bound is 14.24 mmHg. We do not yet know where in that range the true effect sits.
Peppermint oil is biologically plausible for vascular effects. Menthol activates TRPM8 receptors on vascular smooth muscle, and animal studies show menthol can promote vasodilation. So this is not a result that came out of nowhere. But plausible plus a small positive trial is not the same as established treatment.
The naturopathic lens
Blood pressure is one of those areas where I want my patients to take the research seriously in both directions. A reading of 130/85 is not a number to ignore, and it is also not a number that should make anyone panic. Stage 1 hypertension is the window where lifestyle change has the highest expected return relative to medication, and where I spend a lot of clinic time on the unsexy basics: sodium intake, potassium intake, sleep architecture, alcohol load, body composition, stress regulation, and movement.
Adding peppermint oil to that conversation is reasonable to bring up. Removing one of the well-established interventions in favor of it is not. If a patient is already on antihypertensive medication, peppermint oil is not a substitute for that medication and should not be started without telling the prescribing clinician. Peppermint oil interacts with the cytochrome P450 enzyme system, particularly CYP3A4, which is the same enzyme that metabolizes many cardiovascular drugs. The interaction risk is documented, not theoretical.
There is also a quality question. The trial used a standardized peppermint oil at a specified dose. Over-the-counter peppermint oil capsules vary widely in menthol content, in the carrier oil, and in whether they are enteric-coated for gut delivery versus designed for systemic absorption. A drugstore bottle is not the same product as the one studied.
How to apply this now
A few practical takeaways:
If your blood pressure runs in the prehypertension or stage 1 range, get a home cuff and start tracking. A single in-clinic reading is not a diagnosis. Twenty readings across two weeks give you signal.
Audit the high-yield lifestyle pieces first: sodium under 2,300 mg per day, potassium-rich foods at every meal, alcohol at or below one drink per day, seven to nine hours of sleep, and 150 minutes per week of moderate movement.
If you want to try peppermint oil as an add-on, talk to a clinician who knows your full medication list. This is especially important if you are on any blood pressure medication, blood thinner, statin, or immunosuppressant.
Watch for the next, larger trial. A 20-day pilot is a signal to do a six-month, several-hundred-person study. That is the study we actually need.
A small positive trial is an invitation to look more closely, not a reason to change a protocol. This one earns the look.
Frequently asked questions
Should I start taking peppermint oil for my blood pressure?
Not on your own, and not as a swap for something that is already working. This was one small, short trial. If you are curious, the right move is to bring it to a clinician who knows your full medication list, rather than starting a drugstore bottle on a hunch.
How much peppermint oil did the study use?
The trial used 100 microliters of standardized peppermint oil per day, split into two doses, for 20 days. That is a specific preparation at a specific dose. An over-the-counter capsule off the shelf is rarely the same product, and the amount on the label may not match what was studied.
Can peppermint oil interfere with my medications?
Yes. Peppermint oil is processed by the same liver enzyme system (CYP3A4) that handles many cardiovascular drugs, so it can push those drug levels up or down. If you take blood pressure medication, a blood thinner, a statin, or an immunosuppressant, this is a conversation to have before you try anything.
What actually lowers blood pressure the most in this range?
The unglamorous basics still do the heavy lifting: less sodium, more potassium from food, good sleep, limited alcohol, regular movement, and attention to body composition and stress. Peppermint oil, if it holds up in a bigger trial, would be a small add-on to that foundation, not a replacement for it.
Is peppermint tea the same as the oil they studied?
No. The trial tested a standardized oral peppermint oil, not tea, candies, or topical products. Those forms deliver very different amounts of the active compounds, so you cannot assume a cup of peppermint tea does what the studied oil did.
References
Sinclair J, Sant B, Du X, et al. 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:10.1371/journal.pone.0344538.
Disclaimer
This article is for educational purposes only. It is not medical advice, does not create a clinician-patient relationship, and is not a substitute for individualized care from your own provider. People with hypertension or prehypertension should not start, stop, or adjust any medication or supplement, including peppermint oil, without direct guidance from their prescribing clinician. Peppermint oil can interact with prescription medications and is not appropriate for everyone.
Related reading
Reviewed by Joyce Knieff, ND, LAc on 2026-06-25.
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A validated home upper-arm monitor is the simplest way to gather your own readings across two weeks instead of leaning on a single number at the office, which is exactly the kind of tracking this post describes.
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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