Take peppermint oil for hypertension, new study suggests: Here’s why

For this study, researchers recruited 40 adults who had either elevated blood pressure, also sometimes referred to as “pre-hypertension,” and stage 1 hypertension.

According to the American Heart Association (AHA), elevated blood pressure occurs when a person’s systolic blood pressure is between 120–129 millimeters of mercury (mmHg) and diastolic blood pressure under 80 mmHg, while stage 1 is defined by a systolic blood pressure between 130-139 mmHg and diastolic pressure between 80-89 mmHg.

Study participants were randomly selected to receive either 100 microliters (μL) per day of either peppermint oil or a peppermint-flavored placebo.

“We were interested in peppermint oil because peppermint contains biologically active compounds, particularly menthol and flavonoids, that have plausible relevance to blood pressure regulation,” Jonathan Sinclair, DSc, PhD, course leader MSc sport and exercise sciences at the University of Lancashire in the United Kingdom, and lead author of this study, told Medical News Today.

“Previous research has suggested that peppermint may have antioxidant, anti-inflammatory, smooth muscle relaxant, and vasodilatory properties, all of which are potentially relevant to hypertension,” Sinclair added.

“Our group had also previously conducted a placebo-controlled trial in healthy individuals, where peppermint oil supplementation was associated with reductions in systolic blood pressure,” he continued.

“That provided a strong rationale to examine whether similar effects could be observed in a population where blood pressure reduction is more clinically relevant: individuals with pre-[hypertension, also commonly referred to as ‘elevated blood pressure’] and stage 1 hypertension,” Sinclair detailed.

After 20 days, researchers found the study participants taking peppermint oil lowered their systolic blood pressure by an average of 8.5 mmHg.

“The reduction in systolic blood pressure was important because systolic blood pressure is a major predictor of cardiovascular risk, and even relatively modest reductions can be meaningful at a population level,” Sinclair explained.

“In our trial, after adjusting for baseline values, systolic blood pressure at 20 days was approximately 8.5 mmHg lower in the peppermint group compared with placebo, which is a sizable short-term effect. This finding suggests that peppermint oil supplementation may have the potential to support blood pressure reduction in people with pre- and stage one hypertension.”

– Jonathan Sinclair, DSc, PhD

Additionally, scientists discovered that study participants taking peppermint oil also experienced significantly lower resting heart rates after 20 days.

“Resting heart rate is an important cardiovascular marker because a higher resting heart rate has been associated in epidemiological research with increased cardiovascular and all-cause mortality risk,” Sinclair said.

“In our study, resting heart rate was significantly lower in the peppermint group compared with placebo after the 20-day intervention, which suggests that peppermint oil may have influenced not only vascular tone but also cardiovascular regulation more broadly,” he noted.

If peppermint oil is able to help lower a person’s blood pressure, how does it work?

Sinclair said the most plausible explanation relates to menthol, one of the main bioactive constituents of peppermint oil.

“Menthol can activate TRPM8 channels, which are found in vascular and sensory tissues, and this activation may contribute to vasodilation through calcium-dependent endothelial signalling, nitric oxide-related pathways, and relaxation of vascular smooth muscle,” he explained. “In simple terms, peppermint oil may help blood vessels relax, which could reduce the pressure against which the heart has to pump.”

“However, our trial was not designed to directly measure these mechanisms, so while the biological rationale is strong, future studies should include measures such as endothelial function, nitric oxide metabolites, vascular stiffness, and autonomic markers to establish how peppermint oil may be exerting these effects,” Sinclair added.

MNT had the opportunity to speak with Craig Basman, MD, FACC, FSCAI, associate director of the Structural and Congenital Heart Program at Hackensack University Medical Center in New Jersey, about this study, who commented his initial reaction was one of cautious optimism.

“The findings that a simple, inexpensive, and widely available substance like peppermint oil could potentially lower blood pressure are certainly intriguing,” Basman, who was not involved in this research, said.

According to him: “It’s promising to see a study that is a randomized controlled trial, which is the gold standard for clinical research. However, it is a small study of only 40 patients, so while the results are encouraging, they are not definitive.”

“The best initial treatment for high blood pressure should be non-pharmacological approaches. Medications are mostly safe and effective, but they come with cost, compliance issues, and side effects. Oftentimes we can avoid medications with lifestyle modifications such as diet and exercise, which are the cornerstones of blood pressure management. These nonmedicinal options can empower patients to take a more active role in their own health and can be more accessible and affordable for many people.”

– Craig Basman, MD, FACC, FSCAI

For future research, Basman said the most important next step is to see this research replicated in a larger, more diverse population.

“A study with more participants would provide more robust data and help to confirm these initial findings,” he detailed. “It would also be beneficial to see longer-term studies to understand if the effects of peppermint oil on blood pressure are sustained over time and to identify any potential long-term side effects.”

“Additionally, research into the mechanism of action — how exactly peppermint oil is working to lower blood pressure — would be valuable,” Basman added. “This could lead to a better understanding of its effects and potentially to the development of more targeted therapies in the future.”