HypertensionNCT05561543
Effects of Peppermint Oil in Mild-moderate Hypertension.
A study testing Peppermint oil in people with Hypertension, run by University of Central Lancashire at 1 site in United Kingdom.
Trial summary
Cardiovascular and associated hypertensive diseases are the leading health burden and cause of mortality worldwide; therefore, the necessity for effective interventions is paramount. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Hypertension
- What is being tested?
- Peppermint oil
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 40 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 Jan 2024to 10 Aug 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Aged from 18-65 years
- Systolic blood pressure 120 to 139 mmHg
- Not taking prescribed medicine for blood pressure management
- have the ability to complete written questionnaires independently
- Able to provide informed consent
Who cannot join
- 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 6 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 severe hypertension related target organ damage requiring specialist management
- pregnant or lactating women
Show all 12Show fewer
- allergy to peppermint
- habitual consumption of peppermint products
- regular consumption of antioxidant supplements
- body mass index larger than 40.0 kg/m²
- current enrolment in other clinical trials or use of other external therapies likely to influence outcomes
- condition(s) likely to compromise informed consent, protocol compliance, or outcome assessment, including severe psychiatric illness, cognitive impairment, or active substance or alcohol misuse.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University of Central Lancashire
Preston, Lancashire, PR4 0PE
About this study
Official title: Effects of Peppermint Oil in Cardiometabolic Outcomes in Participants With Mild-moderate Hypertension.
Cardiovascular and associated hypertensive diseases are the leading health burden and cause of mortality worldwide; therefore, the necessity for effective interventions is paramount. Dietary interventions to improve cardiovascular health are highly sought after as they possess less risk and financial burden than pharmacological drugs. Our previous randomized trial has shown that oral peppermint can improving systolic blood pressure and other cardiovascular/ blood lipids in healthy individuals. However, to date, no research has explored this using a placebo randomized intervention in patients with hypertension.
Therefore, the primary purpose of the proposed investigation is to test the ability of oral peppermint oil supplementation to improve cardiometabolic parameters in participants with mild-moderate hypertension.
- Conditions
- Hypertension
- Being tested
- Peppermint oil, Placebo
- Medical subject headings
- Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Peppermint oilDietary supplement
Peppermint oil
PlaceboOther
Placebo
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Identical in taste and colour to the supplement juice, but with no peppermint content. Receives: Other: Placebo |
| Peppermint oil | Experimental | 50 uL of peppermint oil, which will be diluted with 100 mL of water - taken twice per day. Receives: Dietary Supplement: Peppermint oil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Systolic blood pressure
Systolic blood pressure - measured using a digital blood pressure monitor
Measured: Baseline
Systolic blood pressure
Systolic blood pressure - measured using a digital blood pressure monitor
Measured: 20 days
Secondary outcomes (32)
Diastolic blood pressure
Diastolic blood pressure - measured using a digital blood pressure monitor
Measured: Baseline
Diastolic blood pressure
Diastolic blood pressure - measured using a digital blood pressure monitor
Measured: 20 days
Percent bodyfat and fat mass
Participants percentage composition of fat - measured using bio-electrical impedance
Measured: Baseline
Percent bodyfat and fat mass
Participants percentage composition of fat - measured using bio-electrical impedance
Measured: 20 days
Waist circumference
Waist circumference - measured using anthropocentric tape
Measured: Baseline
Waist circumference
Waist circumference - measured using anthropocentric tape
Measured: 20 days
Waist to hip ratio
Ratio of waist to hip circumference - measured using anthropocentric tape
Measured: Baseline
Waist to hip ratio
Ratio of waist to hip circumference - measured using anthropocentric tape
Measured: 20 days
Blood glucose
Capillary blood glucose - mmol/L
Measured: Baseline
Blood glucose
Capillary blood glucose - mmol/L
Measured: 20 days
Blood triglycerides
Capillary blood triglycerides - mmol/L
Measured: Baseline
Blood triglycerides
Capillary blood triglycerides - mmol/L
Measured: 20 days
Blood cholesterol (Total, HDL & LDL)
Capillary blood cholesterol - mmol/L
Measured: Baseline
Blood cholesterol (Total, HDL & LDL)
Capillary blood cholesterol - mmol/L
Measured: 20 days
Total and HDL cholesterol ratio
Ratio of total cholesterol to HDL cholesterol
Measured: Baseline
Total and HDL cholesterol ratio
Ratio of total cholesterol to HDL cholesterol
Measured: 20 days
LDL and HDL cholesterol ratio
Ratio of LDL to HDL cholesterol
Measured: Baseline
Total and HDL cholesterol ratio
Ratio of LDL to HDL cholesterol
Measured: 20 days
Triglyceride glucose index
Log transformed measurement of the blood glucose and blood triglyceride measures outlined above.
Measured: Baseline
Triglyceride glucose index
Log transformed measurement of the blood glucose and blood triglyceride measures outlined above.
Measured: 20 days
Coop-Wonka chart
Psychological wellbeing - The Coop-Wonka chart is a six item questionnaire with a 1-5 scoring system for each thus the chart has a maximum score of 30 which indicates the lowest possible psychological Wellbeing.
Measured: Baseline
Coop-Wonka chart
Psychological wellbeing - The Coop-Wonka chart is a six item questionnaire with a 1-5 scoring system for each thus the chart has a maximum score of 30 which indicates the lowest possible psychological Wellbeing.
Measured: 20 days
Beck Depression Inventory
Psychological wellbeing - the Beck Depression Inventory is a 21 questionnaire with questions that range in scoring from 0-3, thus the maximum score is 63 which is the highest depression score possible.
Measured: Baseline
Beck Depression Inventory
Psychological wellbeing - the Beck Depression Inventory is a 21 questionnaire with questions that range in scoring from 0-3, thus the maximum score is 63 which is the highest depression score possible.
Measured: 20 days
State Trait Anxiety Inventory
Psychological wellbeing - the state trait anxiety inventory is a 40 item questionnaire with each question having a 1-4 score system, thus the maximum score is 80 which indicates the highest level of anxiety.
Measured: Baseline
State Trait Anxiety Inventory
Psychological wellbeing - the state trait anxiety inventory is a 40 item questionnaire with each question having a 1-4 score system, thus the maximum score is 80 which indicates the highest level of anxiety.
Measured: 20 days
Insomnia Severity Index
Sleep quality - The Insomnia Severity Index is a brief instrument designed to assess the severity of both nighttime and daytime components of insomnia. The Insomnia Severity Index is a 7-item self-report questionnaire yielding a total score ranging from 0 to 28.
Measured: Baseline
Insomnia Severity Index
Sleep quality - The Insomnia Severity Index is a brief instrument designed to assess the severity of both nighttime and daytime components of insomnia. The Insomnia Severity Index is a 7-item self-report questionnaire yielding a total score ranging from 0 to 28.
Measured: 20 days
Pittsburgh Sleep Quality Index
Sleep quality - The Pittsburgh Sleep Quality index, is a questionnaire that consists of 19 self-rated questions, grouped into 7 components. Each component is scored separately, weighted equally on a 0 - 3 scale and the scores of the 7 components are then added to give a global score, which has a range of 0 - 21 with higher scores indicating worse sleep quality.
Measured: Baseline
Pittsburgh Sleep Quality Index
Sleep quality - The Pittsburgh Sleep Quality index, is a questionnaire that consists of 19 self-rated questions, grouped into 7 components. Each component is scored separately, weighted equally on a 0 - 3 scale and the scores of the 7 components are then added to give a global score, which has a range of 0 - 21 with higher scores indicating worse sleep quality.
Measured: 20 days
Epworth Sleepiness Scale
Sleep quality - The Epworth Sleepiness Scale is a self-administered questionnaire with 8 questions. Respondents are asked to rate, on a 4-point scale (0-3) with a maximum score of 24.
Measured: Baseline
Epworth Sleepiness Scale
Sleep quality - The Epworth Sleepiness Scale is a self-administered questionnaire with 8 questions. Respondents are asked to rate, on a 4-point scale (0-3) with a maximum score of 24.
Measured: 20 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Sep 2022
- Study start1 Jan 2024
- Primary completion1 Aug 2025
- Study completion10 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for HypertensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Central Lancashire
- Sponsor type
- University, hospital or other
- Collaborators
- University of Hertfordshire
- Responsible party
- Principal investigator, Jonathan Sinclair, University of Central Lancashire
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05561543
- Sponsor's protocol ID
- Peppermint oil hypertension
- Status last verified
- Jan 2026
- First submitted
- 26 Sep 2022
- Last updated
- 15 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
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 Apr 23;21(4):e0344538. doi: 10.1371/journal.pone.0344538. eCollection 2026.
PubMed 42024666Sinclair 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 May 7;20(5):e0321986. doi: 10.1371/journal.pone.0321986. eCollection 2025.
PubMed 40333716
Study at a glance
From the registry record, last updated by the sponsor on 15 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Peppermint Oil in Cardiometabolic Outcomes in Participants With Mild-moderate Hypertension.
- ClinicalTrials.gov ID
- NCT05561543
- Acronym / sponsor ID
- Peppermint oil hypertension
- Conditions
- Hypertension
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- University of Central LancashireUniversity, hospital or other
- Collaborators
- University of Hertfordshire
- Study start
- 1 Jan 2024 (actual)
- Primary completion
- 1 Aug 2025 (actual)
- Study completion
- 10 Aug 2025 (actual)
- First posted
- 30 Sep 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Cardiovascular and associated hypertensive diseases are the leading health burden and cause of mortality worldwide; therefore, the necessity for effective interventions is paramount. Dietary interventions to improve cardiovascular health are highly sought after as they possess less risk and financial burden than pharmacological drugs. Our previous randomized trial has shown that oral peppermint can improving systolic blood pressure and other cardiovascular/ blood lipids in healthy individuals. However, to date, no research has explored this using a placebo randomized intervention in patients with hypertension.
Therefore, the primary purpose of the proposed investigation is to test the ability of oral peppermint oil supplementation to improve cardiometabolic parameters in participants with mild-moderate hypertension.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Other: PlaceboIdentical in taste and colour to the supplement juice, but with no peppermint content. |
| Peppermint oil | Experimental | Dietary Supplement: Peppermint oil50 uL of peppermint oil, which will be diluted with 100 mL of water - taken twice per day. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Aged from 18-65 years
- Systolic blood pressure 120 to 139 mmHg
- Not taking prescribed medicine for blood pressure management
- have the ability to complete written questionnaires independently
- Able to provide informed consent
Key exclusion criteria (12 listed)
- 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 6 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 severe hypertension related target organ damage requiring specialist management
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Peppermint oilPeppermint oil | Dietary supplement | Peppermint oil |
| PlaceboPlacebo | Other | Placebo |
Primary outcome
Systolic blood pressure
Time frame: Baseline
Systolic blood pressure - measured using a digital blood pressure monitor
Systolic blood pressure
Time frame: 20 days
Systolic blood pressure - measured using a digital blood pressure monitor
32 secondary outcomes
Diastolic blood pressure
Time frame: Baseline
Diastolic blood pressure
Time frame: 20 days
Percent bodyfat and fat mass
Time frame: Baseline
Percent bodyfat and fat mass
Time frame: 20 days
Waist circumference
Time frame: Baseline
Waist circumference
Time frame: 20 days
Waist to hip ratio
Time frame: Baseline
Waist to hip ratio
Time frame: 20 days
Blood glucose
Time frame: Baseline
Blood glucose
Time frame: 20 days
Blood triglycerides
Time frame: Baseline
Blood triglycerides
Time frame: 20 days
Blood cholesterol (Total, HDL & LDL)
Time frame: Baseline
Blood cholesterol (Total, HDL & LDL)
Time frame: 20 days
Total and HDL cholesterol ratio
Time frame: Baseline
Total and HDL cholesterol ratio
Time frame: 20 days
LDL and HDL cholesterol ratio
Time frame: Baseline
Total and HDL cholesterol ratio
Time frame: 20 days
Triglyceride glucose index
Time frame: Baseline
Triglyceride glucose index
Time frame: 20 days
Coop-Wonka chart
Time frame: Baseline
Coop-Wonka chart
Time frame: 20 days
Beck Depression Inventory
Time frame: Baseline
Beck Depression Inventory
Time frame: 20 days
State Trait Anxiety Inventory
Time frame: Baseline
State Trait Anxiety Inventory
Time frame: 20 days
Insomnia Severity Index
Time frame: Baseline
Insomnia Severity Index
Time frame: 20 days
Pittsburgh Sleep Quality Index
Time frame: Baseline
Pittsburgh Sleep Quality Index
Time frame: 20 days
Epworth Sleepiness Scale
Time frame: Baseline
Epworth Sleepiness Scale
Time frame: 20 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Jan 2026.
- Derived from this study: PubMed 42024666Sinclair 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 Apr 23;21(4):e0344538. doi: 10.1371/journal.pone.0344538. eCollection 2026.
- Derived from this study: PubMed 40333716Sinclair 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 May 7;20(5):e0321986. doi: 10.1371/journal.pone.0321986. eCollection 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Peppermint oil in people with Hypertension, run by University of Central Lancashire at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Systolic blood pressure (time frame: Baseline). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05561543, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Jan 2026.