Randomized trial shows peppermint oil reduces systolic blood pressure in adults with hypertension — Evidence Review
Published in PLOS One, by researchers from University of Lancashire
Researched by
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Table of Contents
Daily peppermint oil supplementation reduced systolic blood pressure in adults with mildly elevated levels, according to a new randomized controlled trial. Related research generally supports the potential for peppermint and other herbal remedies to modestly lower blood pressure, although the overall evidence base remains mixed and further studies are warranted; see the original study at PLOS One.
- Several prior studies—including both human trials and systematic reviews—indicate that peppermint and other herbs may reduce systolic blood pressure, particularly in individuals with prehypertension or mild hypertension, supporting the new findings 1 3 5 8.
- The magnitude of blood pressure reduction seen in the new study is somewhat larger than in some earlier trials, though similar improvements in cardiometabolic health and anxiety have also been reported with peppermint oil supplementation 5.
- Broader meta-analyses and reviews suggest that while certain herbal supplements can lower blood pressure, effects vary by population and specific intervention, highlighting the need for more high-quality trials to confirm these results and determine long-term safety 3 13.
Study Overview and Key Findings
Hypertension is a leading cause of cardiovascular disease and mortality worldwide, and finding accessible, well-tolerated, and cost-effective interventions is a public health priority. Many individuals with mildly elevated blood pressure may not qualify for or tolerate conventional antihypertensive medications, making alternative strategies of particular interest. In this context, researchers at the University of Lancashire conducted a 20-day, randomized, placebo-controlled trial to assess whether daily peppermint oil supplementation could lower blood pressure in adults with prehypertension or stage 1 hypertension.
The study evaluated not only systolic and diastolic blood pressure, but also included secondary outcomes such as heart rate, mental well-being, and sleep quality. The findings suggest peppermint oil may offer a simple, inexpensive adjunct for blood pressure management in certain populations.
| Property | Value |
|---|---|
| Organization | University of Lancashire |
| Journal Name | PLOS One |
| Authors | Dr. Jonnie Sinclair |
| Population | Adults with prehypertension or stage 1 hypertension |
| Sample Size | 40 adults |
| Methods | Randomized Controlled Trial (RCT) |
| Outcome | Systolic and diastolic blood pressure, heart rate, mental well-being, sleep quality |
| Results | Systolic blood pressure reduced by an average of 8.5mmHg |
Literature Review: Related Studies
To place these findings in context, we searched the Consensus database—which includes over 200 million research papers—using the following queries:
- peppermint oil blood pressure reduction
- systolic blood pressure peppermint oil
- natural remedies hypertension outcomes
Below, we summarize key findings from related research, grouped by major topic areas:
| Topic | Key Findings |
|---|---|
| Does peppermint oil supplementation lower blood pressure? | - Multiple RCTs and experimental studies have found modest reductions in systolic blood pressure with peppermint oil supplementation, whether ingested or inhaled, particularly in individuals with prehypertension or mild hypertension 1 2 5 8. - Effects are most pronounced in hypertensive populations and may be smaller or absent in normotensive individuals 3 5. |
| How do herbal and natural remedies compare to standard antihypertensive treatments? | - Some herbal remedies, such as Songling Xuemaikang capsule (SXC), have demonstrated noninferiority to standard drugs like losartan in mild hypertension, with comparable blood pressure reductions and similar safety profiles 9. - Systematic reviews and meta-analyses suggest certain herbs and supplements can reduce blood pressure, especially in hypertensive or prehypertensive populations, but evidence is mixed and effects are often less robust than pharmaceuticals 3 11 12 13. |
| What are the broader cardiometabolic and psychological effects of peppermint oil? | - Peppermint oil supplementation may improve cardiometabolic health beyond blood pressure, including reductions in triglycerides and improvements in anxiety indices 4 5. - Studies report additional benefits, such as enhanced exercise performance and reduced stress or anxiety, which could contribute indirectly to cardiovascular health 2 5. |
| What mechanisms might explain the antihypertensive effects of peppermint or other herbs? | - The antihypertensive effects of peppermint and related herbs may be mediated by vasorelaxation, reduction of oxidative stress, and relaxation of smooth muscle, potentially via active compounds like menthol and flavonoids 2 10 11. - Similar mechanisms have been proposed for other herbal interventions, such as Moringa oleifera and Melissa officinalis, which have both demonstrated blood pressure lowering in clinical and preclinical studies 6 10. |
Does peppermint oil supplementation lower blood pressure?
The related studies generally support the finding that peppermint oil can reduce systolic blood pressure, particularly in individuals with prehypertension or mild hypertension. Both oral and inhaled forms of peppermint have been studied, with most trials reporting modest but statistically significant reductions in blood pressure compared to placebo or baseline.
- The new RCT’s observed reduction of 8.5 mmHg is larger than reductions reported in some previous trials, but falls within the range of effects seen in other studies of herbal interventions for blood pressure 3 5.
- Non-randomized studies of peppermint inhalation also show decreases in systolic blood pressure and improved stress markers 1.
- A recent RCT using a lower peppermint oil dose (50 μL twice daily) found a significant but smaller reduction in systolic blood pressure (about 4.5 mmHg) 5.
- Systematic reviews confirm that blood pressure reductions are more likely in hypertensive or prehypertensive individuals than in normotensive populations 3.
How do herbal and natural remedies compare to standard antihypertensive treatments?
Some herbal formulations have demonstrated comparable efficacy to standard antihypertensive drugs in mild hypertension, though the evidence base is less robust and long-term safety data are limited.
- In a large, multicenter RCT, a Chinese herbal formula (SXC) was found to be noninferior to losartan in lowering blood pressure over eight weeks, with similar side effect profiles 9.
- Systematic reviews and meta-analyses have found that certain herbs and supplements, such as resveratrol and beetroot juice, can lower blood pressure, but the size of the effect and consistency across studies varies 3 13.
- Reviews emphasize that herbal interventions may be most beneficial for those with elevated blood pressure, with little risk of inducing hypotension in normotensive individuals 3 11.
- Most authors highlight dosing and formulation differences as potential sources of variability in outcomes 12 13.
What are the broader cardiometabolic and psychological effects of peppermint oil?
Beyond blood pressure, peppermint oil and other herbal supplements may offer additional health benefits, particularly for cardiometabolic and psychological well-being.
- Peppermint oil supplementation has been associated with reductions in triglyceride levels and improvements in both state and trait anxiety 5.
- Some studies have observed beneficial effects on exercise performance, glycemic control, lipid profiles, and BMI with peppermint interventions 2 4.
- Improvements in psychological well-being and sleep quality were measured as secondary outcomes in the new study, reflecting a growing interest in holistic health impacts 5.
- While these effects may contribute indirectly to cardiovascular health, they require further confirmation in larger trials 5 13.
What mechanisms might explain the antihypertensive effects of peppermint or other herbs?
The plausible biological mechanisms underlying the antihypertensive effects of peppermint and related herbs involve several pathways:
- Peppermint contains menthol and flavonoids, which may relax vascular smooth muscle and promote vasodilation, thus reducing blood pressure 2 11.
- Other herbs, such as Moringa oleifera and Melissa officinalis, have demonstrated antihypertensive effects via antioxidant activity, improved endothelial function, and reduced vascular resistance in both animal and human studies 6 10.
- Studies of aroma oil inhalation (including peppermint) show changes in brain activity associated with relaxation and stress reduction, potentially contributing to lower blood pressure 1.
- The safety profile of these interventions appears favorable in short-term studies, but long-term effects and interactions with medications require further investigation 6 11.
Future Research Questions
While the current study provides promising evidence for the use of peppermint oil in managing mildly elevated blood pressure, several important questions remain. Further research is needed to determine the long-term safety, optimal dosing, mechanisms of action, and real-world effectiveness of peppermint oil and similar herbal interventions in diverse populations.
| Research Question | Relevance |
|---|---|
| What are the long-term safety and efficacy outcomes of daily peppermint oil supplementation for blood pressure management? | Long-term data are lacking; most studies focus on short interventions (≤30 days), so potential benefits or risks over months or years remain unknown 3 5 13. |
| How does peppermint oil compare directly to standard antihypertensive medications in head-to-head trials? | There is little direct comparison between peppermint oil and established drugs; such studies could clarify relative efficacy and safety, as has been done for other herbal interventions 9. |
| What are the optimal dose, formulation, and mode of administration for peppermint oil to achieve blood pressure reduction? | Dosing and delivery (oral vs. inhaled) vary widely across studies; determining the most effective and practical approach is important for clinical translation 1 2 5. |
| Does peppermint oil produce similar blood pressure reductions in diverse populations (e.g. older adults, ethnic minorities, those with comorbidities)? | Most studies enroll younger adults without major comorbidities; broader studies are needed to ensure generalizability, especially as hypertension is prevalent in older and more diverse populations 3 11. |
| What are the mechanisms underlying the antihypertensive effect of peppermint oil in humans? | Mechanistic studies could reveal whether effects are driven by vascular, neurological, or metabolic pathways, informing both safety and efficacy optimization 2 10 11. |