Effect of 4 Weeks of Citrulline and Glutathione Supplementation on Arterial Function

October 19, 2022 updated by: Texas Tech University

Effects of 4 Weeks Supplementation With L-Citrulline and Glutathione on Arterial Function and Cardiovascular Responses in Postmenopausal Healthy Women: A Pilot Study

Examining the effects of 4 weeks of Citrulline alone or in combination with glutathione on the arterial function of postmenopausal women.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

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

L-Citrulline is a non-protein amino acid and an efficient precursor of L-arginine, the substrate for endothelial nitric oxide synthesis. Glutathione is a tripeptide with antioxidant effects. Postmenopausal women will ingest 6g/d of L-Citrulline or 2g of L-Citrulline plus 200mg/d of glutathione or placebo (maltodextrin) for 4 weeks with vascular function testing prior to and after the intervention.

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 (Actual)

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.
39

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 Locations

  • United States
    • Texas
      • Lubbock, Texas, United States, 79409
        • TTU Kinesiology and Sport Management Building

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

50 years to 79 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  1. Generally healthy, postmenopausal women (defined as the absence of menstruation for at least 1 year).
  2. Between the ages of 50-79 years.
  3. Body mass index of 18.5 - 34.9 kg/m2.
  4. Brachial systolic blood pressure < 150 mmHg, and diastolic blood pressure < 90 mmHg.
  5. Sedentary (defined as < 120 min/week of exercise).
  6. Be willing and able to comfortably abstain from any of food supplements for the period of time beginning 1 month prior to the study to the time of the termination of the study.
  7. Not participating as a subject in another study for at least 2 months prior to the study and for the duration of this study.

Exclusion Criteria:

  1. Current or prior use of tobacco products, e-cigarettes or other inhaled substance.
  2. Use of medications and/or any supplements that may affect outcome variables (such as arginine-containing supplements, nitroglycerin, statin drugs, but not limited to those.)
  3. Taking hormone replacement therapy during the 3 months before the study.
  4. More than a moderate intake of alcohol (>7 drink per week).
  5. Cardiovascular diseases, diabetes and other metabolic or chronic diseases.
  6. Musculoskeletal disorders that will prevent exercise performance.

  7. Currently taking more than one vasoactive drug for blood pressure control.

    • Subject having no more than one drug for prevention, which does not affect variables, may be included, but will be diagnosed as not having a disease.

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: Double

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: L-Citrulline + Glutathione
Citrulline: 2 grams/day, Glutathione: 200mg/day for 4 weeks
Dietary supplement: L-Citrulline
Four weeks of oral L-Citrulline (2 grams/day) supplementation. Supplementation will be ingested daily, half of the doses in the morning and half at night.
Dietary supplement: L-Citrulline
Four weeks of oral L-Citrulline (6 grams/day) supplementation. Supplementation will be ingested daily, half of the doses in the morning and half at night.
Dietary supplement: Glutathione
Four weeks of Glutathione (200mg/day) supplementation. Supplementation will be ingested daily, half of the doses in the morning and half at night.
Experimental: L-Citrulline
Citrulline: 6 grams/day
Dietary supplement: L-Citrulline
Four weeks of oral L-Citrulline (2 grams/day) supplementation. Supplementation will be ingested daily, half of the doses in the morning and half at night.
Dietary supplement: L-Citrulline
Four weeks of oral L-Citrulline (6 grams/day) supplementation. Supplementation will be ingested daily, half of the doses in the morning and half at night.
Placebo Comparator: Placebo
Maltodextrin: 6 grams/day
Dietary supplement: Placebo
Four weeks of oral placebo (6 grams/day maltodextrin) supplementation. Supplementation will be ingested daily, half of the doses in the morning and half at night.

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
Change in endothelial function
Time Frame: 4 weeks
Endothelial function will be measured before and after the intervention using brachial artery flow mediated dilation at rest, blood flow measured in the brachial artery during handgrip exercise, and blood flow in the common femoral artery during passive leg movement. All measurements performed using doppler ultrasound.
4 weeks
Change in arterial stiffness
Time Frame: 4 weeks
Arterial stiffness will be assessed through measurement of pulse-wave velocity of the carotid-femoral, carotid radial, carotid-ankle and femoral ankle arterial segments before and after the 4 week interventions.
4 weeks
Blood pressure control during the cold pressor test
Time Frame: 4 weeks
Blood pressure will be measured during the cold pressor test before and after the 4 weeks.
4 weeks
L-Arginine bioavailability
Time Frame: 4 weeks
Plasma levels of arginine will be measured before and after the 4 week intervention.
4 weeks

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
cardiovascular hemodynamics using pulse wave analysis during the cold pressor test
Time Frame: 4 weeks
arterial tonometry will be measured during the cold pressor test before and after the 4 week intervention.
4 weeks
body composition
Time Frame: 4 weeks
We will determine whether L-citrulline + glutathione changes body composition more than L-citrulline or placebo.
4 weeks
Muscle Strength
Time Frame: 4 weeks
Leg Extension strength will be measured before and after the 4 weeks.
4 weeks
L-Citrulline levels
Time Frame: 4 weeks
Plasma levels of L-Citrulline will be measured before and after the 4 weeks.
4 weeks
Glutathione peroxidase levels
Time Frame: 4 weeks
Blood levels of glutathione peroxidase will be measured before and after the 4 weeks
4 weeks
Malondialdehyde
Time Frame: 4 weeks
blood levels of malondialdehyde will be measured before and after the 4 weeks
4 weeks
L-Ornithine levels
Time Frame: 4 weeks
plasma levels of L-ornithine will be measured before and after the 4 weeks
4 weeks

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.
Texas Tech University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Kyowa Hakko Bio Co., Ltd.

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 (Actual)

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.
July 1, 2020

Primary Completion (Actual)

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.
April 27, 2022

Study Completion (Actual)

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.
April 27, 2022

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).
December 10, 2020

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.
December 16, 2020

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.
December 17, 2020

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.
October 20, 2022

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.
October 19, 2022

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.
October 1, 2022

More Information

Terms related to this study

Keywords

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.
  • 20-0152

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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