The Effect of Olive Leaf Extract Supplementation on Training-induced Skeletal Muscle Functional and Molecular Adaptations in Healthy Volunteers (OLE_Training_1)

July 22, 2026 updated by: Nicolas Place, University of Lausanne
The goal of this study is to investigate the effect of combining olive leaf extract supplementation with endurance training (moderate intensity continuous training or sprint interval training). We hypothesize that OLE supplementation during training, as compared to training alone with placebo, will translate into better performance outcomes. More specifically, we hypothesize that the additional benefits of OLE supplementation on performance will be mediated by improved mitochondrial characteristics in skeletal muscle and increased neural activation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Maximal exercise capacity (VO2peak) predicts cardiovascular risk and all-cause mortality. Regular moderate to vigorous physical activity, a key determinant of VO2peak, is essential for an optimal health status of the general population. Thus, strategies that accentuate the health benefits of exercise may have considerable therapeutic benefits. Skeletal muscle Ca2+ handling is a primary determinant of exercise capacity. The regulation of skeletal muscle contraction by Ca2+ is coupled to mitochondrial energy production through a mechanism involving transport across the inner mitochondrial membrane by the mitochondrial Ca2+ uniporter (MCU). Ca2+ entry in the mitochondrial matrix controls Ca2+ -sensitive enzymes, including pyruvate dehydrogenase (PDH) activity, a rate-limiting enzyme for glycolysis. Olive leaf extract (OLE) contains ~40% of the natural polyphenol oleuropein and is a potent activator of MCU in skeletal muscle with anti-inflammatory and antioxidant properties. The present study will be a double-blind, randomized, placebo-controlled, parallel study in healthy young individuals (18-45 years) consisting of a 3-week endurance training (either moderate intensity continuous training or sprint interval training) period combined with OLE or placebo intake. We will examine the impact of OLE supplementation on maximal exercise capacity, knee extensor neuromuscular function, muscular and blood adaptations. The results of this study will elucidate whether OLE supplementation improves fitness parameters and the molecular mechanisms regulating these adaptations.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Switzerland
      • Lausanne, Switzerland, 1015
        • Bâtiment Synathlon, quartier UNIL-Centre
        • Contact:
        • Sub-Investigator:
          • Javier Botella, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Being between 18 and 45 years old
  2. Being healthy (assessed through the PAR-Q questionnaire).
  3. Being physically active, but not involved in any structured training program
  4. Being available for the study period.

Exclusion Criteria:

  1. If a participant answers positively to any YES/NO question in the PAR-Q health questionnaire. For questions requiring a precision, any positive answer will be reviewed by a medical doctor, who will determine the inclusion/exclusion of the participant.
  2. Having allergy to xylocaine
  3. Being pregnant.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Sprint interval training group (SIT group)
The model of sprint interval training (SIT) consists of four to six 30 s all-out cycling bouts on a cycle ergometer, with 4 min rests between tests. Three sessions will be performed per week for three weeks.
Dietary supplement: Olive leaf extract
A capsule containing 250 mg of an olive leaf extract preparation will be swallowed with a glass of water daily for 21 days.
Dietary supplement: Placebo
A capsule containing 336 mg of cellulose microcrystalline will be swallowed with a glass of water daily for 21 days.
Experimental: Moderate intensity continuous training (MICT group)
The moderate intensity continuous training (MICT) consists of 40 to 60 min cycling on a cycle ergometer at 50% of the maximal aerobic power output. Three sessions will be performed per week for three weeks.
Dietary supplement: Olive leaf extract
A capsule containing 250 mg of an olive leaf extract preparation will be swallowed with a glass of water daily for 21 days.
Dietary supplement: Placebo
A capsule containing 336 mg of cellulose microcrystalline will be swallowed with a glass of water daily for 21 days.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
maximal aerobic power
Time Frame: before and after the three-week training period
maximal power (in watts) measured during a graded exercise to failure
before and after the three-week training period

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Maximal oxygen uptake
Time Frame: before and after the three-week training period
maximal oxygen uptake (ml/min/kg) measured during a graded exercise until failure
before and after the three-week training period
Submaximal heart rate and power
Time Frame: before and after the three-week training period
heart rate and power measured during submaximal cycling exercise
before and after the three-week training period
Knee extensor neuromuscular function
Time Frame: before and after the three-week training period
maximal voluntary contraction force and maximal voluntary activation level
before and after the three-week training period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Lausanne

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 17, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 22, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 27, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 22, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2026-00654

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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