Dietary ExposureNCT03998800
Effects of L-arginine and L-citrulline Supplementation on Muscle Respiration
A study testing Dietary Supplement and Endurance exercise on a cycle ergometer in people with Dietary Exposure, run by Loughborough University at 1 site in United Kingdom.
Trial summary
The objective of this trial is to determine the effects of dietary supplementation with the amino acids, L-arginine and L-citrulline, on endurance performance and mitochondrial respiration in healthy men compared to supplementation with L-arginine alone and a placebo supplement. Read more about this study
- Who is it for?
- Ages 18 to 40 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Dietary Exposure
- What is being tested?
- Dietary Supplement and Endurance exercise on a cycle ergometer
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 18 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 May 2019to 1 Jan 2022
- 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 40 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- healthy male, 18-40 years of age
- recreationally-active
- healthy BMI (≥18.5 and ≤24.9 kg/m2)
Who cannot join
- participating in other studies currently or in the past two months or has an intention to participate in other studies over the period of this study
- history of gastric, digestive, cardiovascular, renal disease or any other orthopaedic diseases related to motor organs
- lidocaine allergy
- use of medication that may affect study measures
- contraindication to the biopsy procedures
- on medications that affect the immune system
Show all 10Show fewer
- on Aspirin or other drugs known to prolong bleeding
- smoker
- user of dietary supplements currently or in the past one month
- a heavy drinker
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
School of Sport, Exercise and Health Sciences
Loughborough, Leicester, Le11 3YU
About this study
Official title: The Effect of L-arginine and L-citrulline Supplementation on Endurance Performance and Mitochondrial Respiration
The objective of this trial is to determine the effects of dietary supplementation with the amino acids, L-arginine and L-citrulline, on endurance performance and mitochondrial respiration in healthy men compared to supplementation with L-arginine alone and a placebo supplement.
Read the detailed description
This study is a randomized, double-blind, cross over trial of L-arginine and L-citrulline supplementation, L-arginine supplementation alone and placebo supplementation in healthy men. The intervention period will be 8-11 weeks for each participant and a minimum of 15 individuals will be recruited and enrolled to complete the trial. Subjects will complete the experimental protocol described below over 3 individual 10 day supplementation periods, separated by washout periods of approximately 2 weeks. Subjects will ingest corn-starch as a placebo, L-arginine (3g/day) or L-arginine (1.5 g/day) + L-citrulline (1.5g/day). On day 7 of the supplementation period, a skeletal muscle biopsy and blood sample will be obtained from the subjects to investigate mitochondrial function and blood amino acid and nitric oxide levels. On day 10 of the supplementation period, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance. These assessments will be performed to determine the effects of co-ingesting L-arginine and L-citrulline compared to L-arginine alone and placebo administration.
- Conditions
- Dietary Exposure
- Being tested
- Dietary Supplement, Endurance exercise on a cycle ergometer
- Keywords
- Endurance performance, Mitochondrial function, L-arginine, L-citrulline, Healthy males
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dietary SupplementDietary supplement
Dietary Supplement: L-arginine and L-citrulline supplement, L-arginine supplement, or placebo supplement (corn-starch) Subjects will complete 3 individual 10 day supplementation periods, separated by washout periods of approximately 2 weeks.
Endurance exercise on a cycle ergometerBehavioural
On day 10 of each supplementation period, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance.
| Study group | Role | What they receive |
|---|---|---|
| L-arginine and L-citrulline | Experimental | 10 days of supplementation with 1.5 g of L-arginine and 1.5 g of L-citrulline per day Receives: Dietary Supplement: Dietary Supplement; Behavioral: Endurance exercise on a cycle ergometer |
| L-arginine | Experimental | 10 days of supplementation with 3 g of L-arginine per day Receives: Dietary Supplement: Dietary Supplement; Behavioral: Endurance exercise on a cycle ergometer |
| Placebo (corn-starch) | Placebo comparator | 10 days of supplementation with corn-starch Receives: Dietary Supplement: Dietary Supplement; Behavioral: Endurance exercise on a cycle ergometer |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Endurance performance on a cycle ergometer between L-arginine supplementation and placebo supplementation
On day 10 of the supplementation periods, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance
Measured: 8-11 weeks
Change in Endurance performance on a cycle ergometer between L-arginine + L-citrulline supplementation and placebo supplementation
On day 10 of the supplementation periods, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance
Measured: 8-11 weeks
Changes of mitochondrial function in skeletal muscle between L-arginine supplementation and placebo supplementation
On day 7 of the supplementation periods, a skeletal muscle biopsy sample will be obtained from subjects to investigate mitochondrial function.
Measured: 8-11 weeks
Changes of mitochondrial function in skeletal muscle between L-arginine + L-citrulline supplementation and placebo supplementation
On day 7 of the supplementation periods, a skeletal muscle biopsy sample will be obtained from subjects to investigate mitochondrial function.
Measured: 8-11 weeks
Secondary outcomes (6)
Changes of amino acid and nitric oxide biomarkers levels in plasma between L-arginine supplementation and placebo supplementation
On days 7 and 10 of the supplementation periods, a venous blood sample will be obtained from subjects to investigate amino acid and nitric oxide biomarkers levels in plasma.
Measured: 8-11 weeks
Changes of amino acid and nitric oxide biomarkers levels in plasma between L-arginine + L-citrulline supplementation and placebo supplementation
On days 7 and 10 of the supplementation periods, a venous blood sample will be obtained from subjects to investigate amino acid and nitric oxide biomarkers levels in plasma.
Measured: 8-11 weeks
Changes in muscle oxygenation between L-arginine supplementation and placebo supplementation
On day 10 of the supplementation periods, skeletal muscle oxygenation will be assessed using near-infrared spectroscopy to reveal the tissue saturation index during exercise.
Measured: 8-11 weeks
Changes in muscle oxygenation between L-arginine + L-citrulline supplementation and placebo supplementation
On day 10 of the supplementation periods, skeletal muscle oxygenation will be assessed using near-infrared spectroscopy to reveal the tissue saturation index during exercise.
Measured: 8-11 weeks
Changes in subjective feeling during and after exercise between L-arginine supplementation and placebo supplementation
On day 10 of the supplementation period, subjective feeling during (using the 6-20 ratings of perceived exertion scale) and after (using a 100 mm visual analogue scale where 0 mm = no pain and 100 m = maximal pain) exercise will be assessed. Subjective feeling will also be assessed on the morning of day 11 of each supplementation period.
Measured: 8-11 weeks
Changes in subjective feeling during and after exercise between L-arginine + L-citrulline supplementation and placebo supplementation
On day 10 of the supplementation period, subjective feeling during (using the 6-20 ratings of perceived exertion scale) and after (using a 100 mm visual analogue scale where 0 mm = no pain and 100 m = maximal pain) exercise will be assessed. Subjective feeling will also be assessed on the morning of day 11 of each supplementation period.
Measured: 8-11 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Jun 2019
- Study start1 May 2019
- Primary completion1 Jan 2022
- Study completion1 Jan 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Dietary ExposureStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Allocation: Randomized Endpoint Classification: Efficacy Study Intervention Model: Crossover Assignment Masking: Double Blind (Subject, Investigator)
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- Loughborough University
- Sponsor type
- University, hospital or other
- Collaborators
- Kyowa Hakko Bio Co., Ltd.
- Responsible party
- Principal investigator, Stephen Bailey, Loughborough University
- Investigators
- Stephen J Bailey, PhD, Principal investigator, Lecturer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03998800
- Sponsor's protocol ID
- R19-P010
- Status last verified
- Apr 2022
- First submitted
- 18 Jun 2019
- Last updated
- 2 May 2022
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 May 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of L-arginine and L-citrulline Supplementation on Endurance Performance and Mitochondrial Respiration
- ClinicalTrials.gov ID
- NCT03998800
- Acronym / sponsor ID
- R19-P010
- Conditions
- Dietary Exposure
- Keywords
- Endurance performance, Mitochondrial function, L-arginine, L-citrulline, Healthy males
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- Loughborough UniversityUniversity, hospital or other
- Collaborators
- Kyowa Hakko Bio Co., Ltd.
- Study start
- 1 May 2019 (actual)
- Primary completion
- 1 Jan 2022 (actual)
- Study completion
- 1 Jan 2022 (actual)
- First posted
- 26 Jun 2019 (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.
The objective of this trial is to determine the effects of dietary supplementation with the amino acids, L-arginine and L-citrulline, on endurance performance and mitochondrial respiration in healthy men compared to supplementation with L-arginine alone and a placebo supplement.
Detailed description
This study is a randomized, double-blind, cross over trial of L-arginine and L-citrulline supplementation, L-arginine supplementation alone and placebo supplementation in healthy men. The intervention period will be 8-11 weeks for each participant and a minimum of 15 individuals will be recruited and enrolled to complete the trial. Subjects will complete the experimental protocol described below over 3 individual 10 day supplementation periods, separated by washout periods of approximately 2 weeks. Subjects will ingest corn-starch as a placebo, L-arginine (3g/day) or L-arginine (1.5 g/day) + L-citrulline (1.5g/day). On day 7 of the supplementation period, a skeletal muscle biopsy and blood sample will be obtained from the subjects to investigate mitochondrial function and blood amino acid and nitric oxide levels. On day 10 of the supplementation period, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance. These assessments will be performed to determine the effects of co-ingesting L-arginine and L-citrulline compared to L-arginine alone and placebo administration.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
- Model description
- Allocation: Randomized Endpoint Classification: Efficacy Study Intervention Model: Crossover Assignment Masking: Double Blind (Subject, Investigator)
| Arm | Type | Receives |
|---|---|---|
| L-arginine and L-citrulline | Experimental | Dietary Supplement: Dietary Supplement, Behavioral: Endurance exercise on a cycle ergometer10 days of supplementation with 1.5 g of L-arginine and 1.5 g of L-citrulline per day |
| L-arginine | Experimental | Dietary Supplement: Dietary Supplement, Behavioral: Endurance exercise on a cycle ergometer10 days of supplementation with 3 g of L-arginine per day |
| Placebo (corn-starch) | Placebo comparator | Dietary Supplement: Dietary Supplement, Behavioral: Endurance exercise on a cycle ergometer10 days of supplementation with corn-starch |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- healthy male, 18-40 years of age
- recreationally-active
- healthy BMI (≥18.5 and ≤24.9 kg/m2)
Key exclusion criteria (10 listed)
- participating in other studies currently or in the past two months or has an intention to participate in other studies over the period of this study
- history of gastric, digestive, cardiovascular, renal disease or any other orthopaedic diseases related to motor organs
- lidocaine allergy
- use of medication that may affect study measures
- contraindication to the biopsy procedures
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 |
|---|---|---|
| Dietary SupplementDietary Supplement: L-arginine and L-citrulline supplement, L-arginine supplement, or placebo supplement (corn-starch) Subjects will complete 3 individual 10 day supplementation periods, separated by washout periods of approximately 2 weeks. | Dietary supplement | L-arginine, L-arginine and L-citrulline, Placebo (corn-starch) |
| Endurance exercise on a cycle ergometerOn day 10 of each supplementation period, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance. | Behavioural | L-arginine, L-arginine and L-citrulline, Placebo (corn-starch) |
Primary outcome
Change in Endurance performance on a cycle ergometer between L-arginine supplementation and placebo supplementation
Time frame: 8-11 weeks
On day 10 of the supplementation periods, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance
Change in Endurance performance on a cycle ergometer between L-arginine + L-citrulline supplementation and placebo supplementation
Time frame: 8-11 weeks
On day 10 of the supplementation periods, subjects will complete a performance test on a cycle ergometer to investigate their endurance performance
Changes of mitochondrial function in skeletal muscle between L-arginine supplementation and placebo supplementation
Time frame: 8-11 weeks
On day 7 of the supplementation periods, a skeletal muscle biopsy sample will be obtained from subjects to investigate mitochondrial function.
Changes of mitochondrial function in skeletal muscle between L-arginine + L-citrulline supplementation and placebo supplementation
Time frame: 8-11 weeks
On day 7 of the supplementation periods, a skeletal muscle biopsy sample will be obtained from subjects to investigate mitochondrial function.
6 secondary outcomes
Changes of amino acid and nitric oxide biomarkers levels in plasma between L-arginine supplementation and placebo supplementation
Time frame: 8-11 weeks
Changes of amino acid and nitric oxide biomarkers levels in plasma between L-arginine + L-citrulline supplementation and placebo supplementation
Time frame: 8-11 weeks
Changes in muscle oxygenation between L-arginine supplementation and placebo supplementation
Time frame: 8-11 weeks
Changes in muscle oxygenation between L-arginine + L-citrulline supplementation and placebo supplementation
Time frame: 8-11 weeks
Changes in subjective feeling during and after exercise between L-arginine supplementation and placebo supplementation
Time frame: 8-11 weeks
Changes in subjective feeling during and after exercise between L-arginine + L-citrulline supplementation and placebo supplementation
Time frame: 8-11 weeks
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 2 May 2022.
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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.
Stephen J Bailey, PhD principal investigator
Lecturer
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dietary Supplement and Endurance exercise on a cycle ergometer in people with Dietary Exposure, run by Loughborough University 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 3 inclusion and 10 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 2 May 2022. 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?
Change in Endurance performance on a cycle ergometer between L-arginine supplementation and placebo supplementation (time frame: 8-11 weeks). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 2 May 2022.