Effects of Peppermint Oil in Pre-metabolic Syndrome

NCT07815899 | Completed

• 1 other identifier: Peppermint pre-METS
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Cardiovascular and metabolic diseases are leading causes of morbidity and mortality worldwide; therefore, the development of effective preventive interventions is paramount. Pre-metabolic syndrome, characterised by the presence of cardiometabolic risk factors without meeting the full diagnostic criteria for metabolic syndrome, may represent an important opportunity for early intervention. Dietary interventions are particularly attractive because they may carry fewer risks and impose a lower financial burden than pharmacological treatments. Our previous randomised trial showed that oral peppermint oil supplementation improved systolic blood pressure and selected blood lipid parameters in healthy adults. However, no placebo-controlled randomised trial has examined the effects of peppermint oil supplementation in adults with pre-metabolic syndrome. Therefore, the primary purpose of the proposed investigation is to determine whether oral peppermint oil supplementation improves cardiometabolic parameters in adults with pre-metabolic syndrome.

Conditions

Pre-metabolic Syndrome

Outcome Measures

Primary Outcomes (2)

• Systolic blood pressure

  Systolic blood pressure - measured using a digital blood pressure monitor

  Baseline

• Systolic blood pressure

  Systolic blood pressure - measured using a digital blood pressure monitor

  20 days

Secondary Outcomes (32)

• Diastolic blood pressure

  Baseline

• Diastolic blood pressure

  20 days

• Percent bodyfat and fat mass

  Baseline

• Percent bodyfat and fat mass

  20 days

• Waist circumference

  Baseline

Study Arms (2)

Peppermint oil

EXPERIMENTAL

50 uL of peppermint oil, which will be diluted with 100 mL of water - taken twice per day.

Dietary Supplement: Peppermint Oil

Placebo

PLACEBO COMPARATOR

Identical in taste and colour to the supplement juice, but with no peppermint content.

Radiation: Placebo

Interventions

Peppermint Oil DIETARY_SUPPLEMENT

50 uL of peppermint oil, which will be diluted with 100 mL of water - taken twice per day.

Peppermint oil

Placebo RADIATION

Identical in taste and colour to the supplement juice, but with no peppermint content.

Placebo

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged 18-65 years. Meet two of the five metabolic syndrome criteria. Not taking prescribed medication specifically intended to manage blood pressure, blood glucose or blood lipids.
• Able to complete written questionnaires independently. Able to provide informed consent.

You may not qualify if:

• Diagnosed diabetes mellitus. Known cardiovascular disease or clinically significant cardiovascular comorbidity, including coronary heart disease, symptomatic heart failure, clinically significant arrhythmia, or a history of stroke or transient ischaemic attack within the previous six months.
• Known or suspected secondary hypertension, including renal, renovascular or endocrine causes.
• Known clinically significant renal impairment or severe hepatic disease. Evidence or history of hypertension-related target-organ damage requiring specialist management.
• Pregnant or lactating. Allergy or known intolerance to peppermint or any ingredient contained in the intervention or placebo.
• Habitual consumption of peppermint products. Regular consumption of antioxidant or other dietary supplements likely to influence cardiometabolic outcomes.
• Body mass index greater than 40.0 kg/m². Current enrolment in another clinical trial or use of another intervention or therapy likely to influence the study outcomes.
• Any condition likely to compromise informed consent, protocol compliance or outcome assessment, including severe psychiatric illness, cognitive impairment, or active substance or alcohol misuse.

Sponsors & Collaborators

• University of Central Lancashire: lead

Study Sites (1)

University of Lancashire

Preston, United Kingdom

Location

MeSH Terms

Interventions

peppermint oil

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: September 6, 2026
• First Posted: September 11, 2026
• Study Start: January 1, 2025
• Primary Completion: August 1, 2026
• Study Completion: September 1, 2026
• Last Updated: September 11, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)