Muscle Protein SynthesisMuscle-fullNCT06721026
Re-evaluation of the Muscle-full Effect During Continuously Elevated Amino Acid Availability in Healthy Young Males
A study testing Continuous intravenous stable isotope amino acid tracer infusion and Amino acid infusion in people with Muscle Protein Synthesis, run by Maastricht University Medical Center at 1 site in Netherlands.
Trial summary
Muscle tissue consists of proteins. These proteins are built up of a collection of smaller building blocks: amino acids. When protein is consumed, it gets digested and absorbed into the blood. The body can use these amino acids, by taking them up from thecirculation. Read more about this study
- Who is it for?
- Ages 18 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Muscle Protein Synthesis
- What is being tested?
- Continuous intravenous stable isotope amino acid tracer infusion and Amino acid infusion
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteNetherlands
- Study dates
- 1 Mar 2025to 1 Feb 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male sex
- Aged between 18 - 35 years
- Healthy (assessed based on routine medical questionnaire)
- BMI between 18.5 - 30 kg/m2
Who cannot join
- A potential subject who meets any of the following criteria will be excluded from participation in this study:
- Smoking
- Involved in progressive exercise training
- A history of neuromuscular problems
- Use of anticoagulants
- Recent (<12 months) participation in amino acid tracer (L-[ring-13C6] phenylalanineand L-[3,5-2H2]-tyrosine) studies
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- Use of medication known to affect (muscle) protein metabolism (e.g. corticosteroids, non-steroidal anti-inflammatory drugs, acne medication)
- Phenylketonuria
- Diagnosed with or history of liver damage
- Diagnosed with or history of severe kidney damage and/or malfunction
- Diagnosed with inability to break down amino acids
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site
Maastricht University Medical Centre+
Maastricht, Limburg, 6229ER
Noortje Boot, MSc
About this study
Muscle tissue consists of proteins. These proteins are built up of a collection of smaller building blocks: amino acids. When protein is consumed, it gets digested and absorbed into the blood. The body can use these amino acids, by taking them up from thecirculation. By consuming sufficient protein through our diet, we ensure that the body is provided with enough amino acids to enable muscle protein building. Sufficient muscle protein synthesis is important for maintaining muscle function and strength.
Previous research has shown that when 20 to 25g of protein is eaten, muscle protein synthesis is maximized. It is therefore recommended to eat 20g of protein per meal. However, it is currently unclear what happens to muscle protein synthesis rates if multiple meals are eaten. When multiple meals are consumed, amino acids appear in the circulation for prolonged period of time.
Theoretically, when there are a high amino acid concentrations in the blood, muscle protein synthesis rates will increase. Contrary to this theory, a study more than 20 years ago showed otherwise. It was observed that muscle protein synthesis rates are only elevated for2 hours afterwhich they decrease again. This phenomenon was referred to as the "muscle-full" effect. Because this phenomenon is in contrast with more previous studies, the objective is to replicate that study. This is important so that nutritional advice for healthy, but also clinical populations in the future can be improved.
- Conditions
- Muscle Protein Synthesis
- Being tested
- Continuous intravenous stable isotope amino acid tracer infusion, Amino acid infusion
- Keywords
- amino acid infusion, tracer methodology, muscle biopsy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Continuous intravenous stable isotope amino acid tracer infusionOther
During the single 12 h trial day, a primed continuous stable isotope infusion will run in order to assess muscle protein synthesis in the basal (4 h) and post-prandial (8 h) state.
Amino acid infusionOther
In order to assess muscle protein synthesis rates during continuous elevated plasma amino acid availability, the amino acid infusion solution Vamin®14 EF will be used. Vamin® 14EF contains 85g amino acids per liter and will be administered in the post-prandial period for 8 hours to ensure a constant rate of amino acid infusion over the full assessment period of the primary outcome measure.
| Study group | Role | What they receive |
|---|---|---|
| Continuous amino acid infusion | Experimental | Tracer infusions combined with infusion of a mixture of amino acids Receives: Other: Continuous intravenous stable isotope amino acid tracer infusion; Other: Amino acid infusion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Muscle protein synthesis during continuous elevated plasma amino acid avaialbility in healthy young males
The primary endpoint is muscle protein synthesis rates (in %/h) over the full assessment period (8 h) as determined with contemporary stable isotope tracer methodology combined with repeated blood and muscle sampling. Muscle protein synthesis are calculated using plasma as precursor pool and the tracer enrichment in the muscle (measured with UPLC and GC-IRMS).
Measured: 8 hours
Secondary outcomes (3)
Basal muscle protein synthesis rates
Basal muscle protein synthesis rates (in %/h) will be assessed over a 3h period as determined with contemporary stable isotope tracer methodology combined with repeated blood and muscle sampling. Muscle protein synthesis are calculated using plasma as precursor pool and the tracer enrichment in the muscle biopsy (measured with UPLC and GC-IRMS).
Measured: 3 hours
Whole-body protein kinetics
Including total rate of appearance, exogenous rate of appearance, endogenous rate of appearance, rate of disappearance based (all expressed as μmol/kg/min) on tracer plasma amino acid concentrations over time (measured with UPLC)
Measured: 8 hours
Whole-body protein metabolism
synthesis, breakdown, oxidation, net balance (all expressed as μmol/kg/h). Based on amino acid concentrations in plasma and breath samples (measured with UPLC and GC-IRMS).
Measured: 8 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Dec 2024
- Study start1 Mar 2025 (estimated)
- Primary completion31 Dec 2025 (estimated)
- Study completion1 Feb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Muscle Protein SynthesisStudies 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
- Not applicable
- Intervention model
- Single group
- Model description
- Cross-sectional, non-therapeutic, intervention study
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Maastricht University Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Luc van Loon, PhD, Principal investigator, Maastricht University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06721026
- Sponsor's protocol ID
- METC24-028
- Acronym
- Muscle-full
- Status last verified
- Dec 2024
- First submitted
- 3 Dec 2024
- Last updated
- 13 Dec 2024
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: Data will be made available upon request
Study at a glance
From the registry record, last updated by the sponsor on 13 Dec 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Re-evaluation of the Muscle-full Effect During Continuously Elevated Amino Acid Availability in Healthy Young Males
- ClinicalTrials.gov ID
- NCT06721026
- Acronym / sponsor ID
- Muscle-full / METC24-028
- Conditions
- Muscle Protein Synthesis
- Keywords
- amino acid infusion, tracer methodology, muscle biopsy
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- Maastricht University Medical CenterUniversity, hospital or other
- Study start
- 1 Mar 2025 (estimated)
- Primary completion
- 31 Dec 2025 (estimated)
- Study completion
- 1 Feb 2026 (estimated)
- First posted
- 6 Dec 2024 (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.
Muscle tissue consists of proteins. These proteins are built up of a collection of smaller building blocks: amino acids. When protein is consumed, it gets digested and absorbed into the blood. The body can use these amino acids, by taking them up from thecirculation. By consuming sufficient protein through our diet, we ensure that the body is provided with enough amino acids to enable muscle protein building. Sufficient muscle protein synthesis is important for maintaining muscle function and strength.
Previous research has shown that when 20 to 25g of protein is eaten, muscle protein synthesis is maximized. It is therefore recommended to eat 20g of protein per meal. However, it is currently unclear what happens to muscle protein synthesis rates if multiple meals are eaten. When multiple meals are consumed, amino acids appear in the circulation for prolonged period of time.
Theoretically, when there are a high amino acid concentrations in the blood, muscle protein synthesis rates will increase. Contrary to this theory, a study more than 20 years ago showed otherwise. It was observed that muscle protein synthesis rates are only elevated for2 hours afterwhich they decrease again. This phenomenon was referred to as the "muscle-full" effect. Because this phenomenon is in contrast with more previous studies, the objective is to replicate that study. This is important so that nutritional advice for healthy, but also clinical populations in the future can be improved.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Cross-sectional, non-therapeutic, intervention study
| Arm | Type | Receives |
|---|---|---|
| Continuous amino acid infusion | Experimental | Other: Continuous intravenous stable isotope amino acid tracer infusion, Other: Amino acid infusionTracer infusions combined with infusion of a mixture of amino acids |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Male sex
- Aged between 18 - 35 years
- Healthy (assessed based on routine medical questionnaire)
- BMI between 18.5 - 30 kg/m2
Key exclusion criteria (11 listed)
- A potential subject who meets any of the following criteria will be excluded from participation in this study:
- Smoking
- Involved in progressive exercise training
- A history of neuromuscular problems
- Use of anticoagulants
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 |
|---|---|---|
| Continuous intravenous stable isotope amino acid tracer infusionDuring the single 12 h trial day, a primed continuous stable isotope infusion will run in order to assess muscle protein synthesis in the basal (4 h) and post-prandial (8 h) state. | Other | Continuous amino acid infusion |
| Amino acid infusionIn order to assess muscle protein synthesis rates during continuous elevated plasma amino acid availability, the amino acid infusion solution Vamin®14 EF will be used. Vamin® 14EF contains 85g amino acids per liter and will be administered in the post-prandial period for 8 hours to ensure a constant rate of amino acid infusion over the full assessment period of the primary outcome measure. | Other | Continuous amino acid infusion |
Primary outcome
Muscle protein synthesis during continuous elevated plasma amino acid avaialbility in healthy young males
Time frame: 8 hours
The primary endpoint is muscle protein synthesis rates (in %/h) over the full assessment period (8 h) as determined with contemporary stable isotope tracer methodology combined with repeated blood and muscle sampling. Muscle protein synthesis are calculated using plasma as precursor pool and the tracer enrichment in the muscle (measured with UPLC and GC-IRMS).
3 secondary outcomes
Basal muscle protein synthesis rates
Time frame: 3 hours
Whole-body protein kinetics
Time frame: 8 hours
Whole-body protein metabolism
Time frame: 8 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Dec 2024.
- Individual participant dataSharing planned: Undecided. Data will be made available upon request
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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.
Luc van Loon, PhD principal investigator
Maastricht University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Continuous intravenous stable isotope amino acid tracer infusion and Amino acid infusion in people with Muscle Protein Synthesis, run by Maastricht University Medical Center at 1 site in Netherlands.
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 4 inclusion and 11 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: opening soon, as of the sponsor's last update on 13 Dec 2024. 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 Netherlands. 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. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Luc van Loon, PhD (0031433881743, l.vanloon@maastrichtuniversity.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Muscle protein synthesis during continuous elevated plasma amino acid avaialbility in healthy young males (time frame: 8 hours). 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 13 Dec 2024; AzTrials last refreshed its copy on 1 Nov 2026.