Evaluation of Sports Supplements on Blood Flow

May 17, 2022 updated by: Michelle Gray, University of Arkansas, Fayetteville

Effects of Nitrosigine on Flow-Mediated Dilation Among Young Adults

Many athletes seek to increase their plasma (blood) nitric oxide content prior to exercise in order to augment vasodilation. Increased vasodilation during exercise, especially high intensity resistance training, allows for more blood flow to muscle tissues, which may give the athlete benefits such as increased work capacity and acute muscle hyperemia, which is commonly referred to as muscle pump. Pre-workout supplements are typically taken 30 minutes to 1 hour prior to the onset of exercise, so the current investigation seeks to determine if citrulline malate or nitrosigine can effect vasodilation within 1 hour of supplementation, and if so, which supplement is more effective. Based on previous findings, we hypothesize that a certain exercise intensity needs to be present for citrulline malate and nitrosigine to have an effect, so a change may not be observable at rest.

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

Data collection will be conducted by qualified research staff and students at the University of Arkansas Exercise Science Research Center (ESRC). Upon contact with the research team, a medical/health questionnaire will be sent via email to the subject. This will be the initial screening tool to determine if the subject qualifies for the project. The subjects must meet the inclusion and none of the exclusion criteria in order to qualify for the study. Participants will be instructed to do the following the day of data collection: 1. No caffeine, stimulants, or blood thinners (such as ibuprofen, advil, aspirin, warfarin, clopidogrel, etc.) 24 hours prior to testing. 2. Wear comfortable clothes (short sleeve top). 3. Take all medication as normal (aside from those mentioned in #1). Participant testing will be conducted as follows: participant arrives at ESRC; height, weight, blood pressure, and complete questionnaires (electronically): medical history, 24-hour dietary recall, International Physical Activity Questionnaire (IPAQ). IPAQ is a standardized questionnaire used to evaluate an individual's level of physical activity in their daily life. After completing all surveys, the subject will be asked to lie in a supine position for 15 minutes, then they will have the diameter of the brachial artery (medial side of upper arm) assessed with ultrasound (GE Logiq e). Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) will be performed. Flow mediated dilation will be performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) will be position on the forearm (just above the wrist) and will be inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff will deflate and vessel diameter will be re-assessed (10 additional trails). Following the initial FMD assessment, one of three supplements will be consumed: citrulline-malate (8 g), Nitrosigine (1.5 g), or placebo (8 g Dextrose). After consumption, participants will remain in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD will be re-assessed.

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.
24

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
    • Arkansas
      • Fayetteville, Arkansas, United States, 72701
        • University of Arkansas

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

18 years to 29 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy, regularly exercising young adults

Exclusion Criteria:

  • hypertension, metabolic disorders, previous consumption of pre-workout supplements 6 months prior to study, prescriptions medications known to effect the vasodilatory response.

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: Other
  • Allocation: Randomized
  • Interventional Model: Crossover 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: Nitrosigine supplementation
Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) was performed. Flow mediated dilation was performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) was position on the forearm (just above the wrist) and was inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff was deflated and vessel diameter was re-assessed (10 additional trails). Following the initial FMD assessment, Nitrosigine (1.5 g) was provided in an 8 ounce solution with a cherry flavoring to mask taste. After consumption, participants remained in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD was re-assessed.
Dietary supplement: inositol-stabilized arginine silicate
Participants were asked to complete the experimental protocol in a 2-hour fasted state. Each participant's brachial artery FMD was assessed twice during each trial, once before supplement ingestion, and again 60 minutes post-ingestion. Male participants were required to wait for a minimum of seven days between trials as a supplement washout period. Female participants reported for supplement trials outside of their follicular phase of the menstrual cycle so that results were not confounded by changes in serum estradiol, which can significantly attenuate flow-mediated dilation. Sixty minutes after supplement consumption, each participant was asked which supplement they thought they had consumed. Participants were also asked whether they experienced any adverse side effects.
Experimental: Citrulline-Malate supplementation
Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) was performed. Flow mediated dilation was performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) was position on the forearm (just above the wrist) and was inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff was deflated and vessel diameter was re-assessed (10 additional trails). Following the initial FMD assessment, Citrulline-Malate (8 g) was provided in an 8 ounce solution with a cherry flavoring to mask taste. After consumption, participants remained in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD was re-assessed.
Dietary supplement: inositol-stabilized arginine silicate
Participants were asked to complete the experimental protocol in a 2-hour fasted state. Each participant's brachial artery FMD was assessed twice during each trial, once before supplement ingestion, and again 60 minutes post-ingestion. Male participants were required to wait for a minimum of seven days between trials as a supplement washout period. Female participants reported for supplement trials outside of their follicular phase of the menstrual cycle so that results were not confounded by changes in serum estradiol, which can significantly attenuate flow-mediated dilation. Sixty minutes after supplement consumption, each participant was asked which supplement they thought they had consumed. Participants were also asked whether they experienced any adverse side effects.
Placebo Comparator: Placebo
Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) was performed. Flow mediated dilation was performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) was position on the forearm (just above the wrist) and was inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff was deflated and vessel diameter was re-assessed (10 additional trails). Following the initial FMD assessment, dextrose (8 g) was provided in an 8 ounce solution with a cherry flavoring to mask taste. After consumption, participants remained in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD was re-assessed.
Dietary supplement: inositol-stabilized arginine silicate
Participants were asked to complete the experimental protocol in a 2-hour fasted state. Each participant's brachial artery FMD was assessed twice during each trial, once before supplement ingestion, and again 60 minutes post-ingestion. Male participants were required to wait for a minimum of seven days between trials as a supplement washout period. Female participants reported for supplement trials outside of their follicular phase of the menstrual cycle so that results were not confounded by changes in serum estradiol, which can significantly attenuate flow-mediated dilation. Sixty minutes after supplement consumption, each participant was asked which supplement they thought they had consumed. Participants were also asked whether they experienced any adverse side effects.

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
Vasodilation
Time Frame: 60 minutes
Amount of brachial vasodilation caused by supplementation as measured by flow-mediated dilation and ultrasound
60 minutes

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 Arkansas, Fayetteville

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michelle Gray, Ph.D, University of Arkansas

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.
October 15, 2018

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.
May 8, 2019

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.
May 8, 2019

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).
February 18, 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.
February 18, 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.
February 20, 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.
May 24, 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.
May 17, 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.
May 1, 2022

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.
  • 1812163576

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

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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