Improvement after a supplement is not the same as a comparative result
Start with the comparison. A before-and-after change alone cannot isolate the contribution of an ingredient.
Citrulline
Exercise performance
Human studies reported between-group improvement in completion time.
Single-ingredient studies · Human studies · between-group comparison
Publications for this result: 1
Other outcomes and study details
Distinct publications linked to this topic: 21
- Route, form, dose, or population details are incomplete, so the findings cannot be confirmed as directly comparable.
What has been studied?
Distinct human comparison papers: 5
Some studies tested several ingredients together. Those results cannot show this ingredient’s separate effect or establish synergy.
completion time
- Comparison result:A better result than the comparison group was reported.General population · Single ingredient
Measurement and study conditions
- Controlled human study
- Randomized trial
- Single ingredient
- General population
- Primary outcome
- Between-group comparison
- Timepoint: 7 days plus dose 1 hour before test
- Study comparison: L-citrulline versus placebo
exercise performance
Research with unclear study subject or type
- A change was reported, but the comparison could not be confirmed.General population · varied
Measurement and study conditions
- Review
- Review
- Unknown intervention
- General population
- Outcome role not specified
- Study subject not identified
- Timepoint: varied
- Study comparison: Some underlying studies report improvement; comparator details not stated in abstract
number of repetitions
Other human research, including observational studies and reviews
- A change was reported before and after use. Its cause cannot be isolated.General population · Combination study
Measurement and study conditions
- Controlled human study
- Randomized trial
- Ingredient combination
- General population
- Primary outcome
- Within-group comparison
- Timepoint: Single training session; repetitions evaluated across 8 sets
- Study comparison: Citrulline-malate versus placebo in the same participants; repetitions increased from the third set
Physical performance
- Comparison result:A better result than the comparison group was reported.Combination study
Measurement and study conditions
- Controlled human study
- Randomized trial
- Ingredient combination
- Unspecified population
- Outcome role not specified
- Between-group comparison
- Timepoint: unspecified
- Study comparison: unspecified
Other measured outcomes (3)
Sprint performance decrement
- Comparison result:A better result than the comparison group was reported.Combination study
Measurement and study conditions
- Controlled human study
- Randomized trial
- Ingredient combination
- Unspecified population
- Outcome role not specified
- Between-group comparison
- Timepoint: unspecified
- Study comparison: unspecified
swimming performance
- Comparison result:No clear difference from the comparison group was found.General population · Single ingredient · Eight days
Measurement and study conditions
- Controlled human study
- Randomized trial
- Single ingredient
- General population
- Primary outcome
- Between-group comparison
- Timepoint: Eight days
- Study comparison: L-citrulline 8 g/day versus placebo; L-arginine was a separate arm
total upper body (the sum of BP and IP) RTF
- Comparison result:A better result than the comparison group was reported.General population · Separable contribution · 6 weeks
Measurement and study conditions
- Controlled human study
- Randomized trial
- Separable contribution
- General population
- Primary outcome
- Between-group comparison
- Timepoint: 6 weeks
- Study comparison: L-citrulline and citrulline malate arms versus placebo; no difference between active arms
This result is held for interpretation. That does not mean research found no effect.
Outcome groups needing additional review (11)
- ergogenic effect · Distinct papers needing additional review: 1Direction unclear: 1
- lean mass · Distinct papers needing additional review: 1Evidence criteria check: 1
- muscle mass · Distinct papers needing additional review: 1Evidence criteria check: 1
- muscle strength · Distinct papers needing additional review: 1Evidence criteria check: 1
- peak power · Distinct papers needing additional review: 1Evidence criteria check: 1
- performance · Distinct papers needing additional review: 1Evidence criteria check: 1
- strength-endurance · Distinct papers needing additional review: 1Evidence criteria check: 1
- time to fatigue · Distinct papers needing additional review: 1Evidence criteria check: 1
- time to reach peak power · Distinct papers needing additional review: 1Direction unclear: 1
- TT time · Distinct papers needing additional review: 1Direction unclear: 1
- TTE · Distinct papers needing additional review: 1Evidence criteria check: 1
One paper can appear under multiple measured outcomes or review reasons, so these counts should not be added together.
Research topics to explore
Research topics to explore
Review findings reported in each research area.
Topics with more linked papers appear first.
- View selected result
Exercise performance
Related papers 21 · human comparison papers 5
- View results
Blood pressure and vascular health
Related papers 16 · human comparison papers 2
- Brachial artery flow-mediated dilation · Improvement reported
- diastolic blood pressure · Improvement reported · Some studies included patients or people with a deficiency
More outcome groups: 8
- View results
Glucose and metabolic health
Related papers 3 · comparison findings need further review
- circulating glucose · Interpretation held
- View results
Fatigue and energy
Related papers 1 · comparison findings need further review
- rate of fatigue · Interpretation held
- View results
Stress and mood
Related papers 1 · comparison findings need further review
Data coverage and detailed study classifications
Paper counts are separated by research topic below. One paper may contribute to multiple findings.
Analysis status: Public-ready
Ingredient analysis date:
How the grade was determined: B
The 61.4 evidence score includes 15 independent human studies and 15 clinical studies in the representative benefit area. The B tier remains conservative because of a meaningful share of null findings in the same benefit area.
The grade is based mainly on the research area with the most evidence. It does not mean the same result was found in other areas.
Papers linked to this ingredient overall: 76
Papers linked to this topic 21 · distinct papers 21 · papers with a confirmed human comparison 5 · papers needing additional review 14
Ingredient-wide papers, topic-linked papers, and sources in outcome groups use different scopes. Adding source counts may count the same paper more than once.
- completion time: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- ergogenic effect: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- exercise performance: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- lean mass: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- muscle mass: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- muscle strength: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- number of repetitions: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- peak power: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- performance: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- Physical performance: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- Sprint performance decrement: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- strength-endurance: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- swimming performance: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- time to fatigue: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- time to reach peak power: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- total upper body (the sum of BP and IP) RTF: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- TT time: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- TTE: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
Exercise performance
What the research found
swimming performance
No clear difference in this measurement was found between the compared groups.
Controlled study in people · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
completion time
The study reported improvement in this measurement.
Controlled study in people · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
number of repetitions
A change was reported before and after use. Its cause cannot be isolated.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Within-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Physical performance
The study reported improvement in this measurement.
Controlled study in people · Ingredient combination · Unspecified population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Sprint performance decrement
The study reported improvement in this measurement.
Controlled study in people · Ingredient combination · Unspecified population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
total upper body (the sum of BP and IP) RTF
The study reported improvement in this measurement.
Controlled study in people · Separable contribution · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
exercise performance
A change was reported, but the comparison could not be confirmed.
Review · Unknown intervention · General population
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
ergogenic effect
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
lean mass
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
muscle mass
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Unspecified population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
muscle strength
The study needs further checking before its result can be interpreted.
Controlled study in people · Separable contribution · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
peak power
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Within-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
performance
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
strength-endurance
The study needs further checking before its result can be interpreted.
Controlled study in people · Separable contribution · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
time to fatigue
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Within-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
time to reach peak power
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
TT time
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · General population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
TTE
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Meta-analysis · Ingredient combination · Unspecified population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Unspecified population
Between-group comparison
Analysis coverage and paper counts
2 papers · 2 measured outcomes
2 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Meta-analysis · Single ingredient · Unspecified population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Blood pressure and vascular health
What the research found
resting BP
A change was reported before and after use. Its cause cannot be isolated.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Within-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Brachial artery flow-mediated dilation
The study reported improvement in this measurement.
Controlled study in people · Single ingredient · Unspecified population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
diastolic blood pressure
The study reported improvement in this measurement.
Controlled study in people · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
SBP
A change was reported, but the comparison could not be confirmed.
Meta-analysis · Unknown intervention · General population
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
atherogenic-endothelial protection
The study needs further checking before its result can be interpreted.
Animal study · indirect · Single ingredient · Unspecified population
This finding comes from animal or cell research. It does not establish the same effect in people.
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
blood pressure
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
blood pressure regulation
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
endothelial senescence
The study needs further checking before its result can be interpreted.
Cell study · indirect · Ingredient combination · Patient group
This finding comes from animal or cell research. It does not establish the same effect in people.
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
endothelial senescence
The study needs further checking before its result can be interpreted.
Cell study · indirect · Single ingredient · Patient group
This finding comes from animal or cell research. It does not establish the same effect in people.
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
FMD
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
sfemFMD
The study needs further checking before its result can be interpreted.
Controlled study in people · Separable contribution · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Unspecified population
Between-group comparison
Analysis coverage and paper counts
4 papers · 4 measured outcomes
4 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Unspecified population
The comparison could not be confirmed.
Analysis coverage and paper counts
2 papers · 2 measured outcomes
2 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Glucose and metabolic health
What the research found
circulating glucose
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Unspecified population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Fatigue and energy
What the research found
rate of fatigue
The study needs further checking before its result can be interpreted.
Controlled study in people · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Stress and mood
What the research found
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Review · Unknown intervention · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
How to read research findings
How should I read research findings?
Research guidesNo clear difference and an uninterpretable result are different
A reported null comparison contains a result. An abstract without an interpretable comparison leaves a question unresolved.
Paper counts and study counts are different
Count original research separately from research that reanalyzes it. Publication volume is neither replication nor a quality rating.
Side effects and combination findings
Findings from this ingredient alone are shown separately from those involving another supplement or medication.
Caution findings
1
Findings from individual and combined use, plus reviewed cautions
Key precautions
No reviewed caution rules are available yet. Reported caution findings are shown below.
These findings were reported in studies. They do not predict an individual's experience.
Findings to review with care
Side effects reported for the ingredient alone are separated from findings involving another supplement or medication.
Side effects reported with this ingredient alone
Symptoms or adverse events reported in studies without another active ingredient.
number of repetitions1 papers
In a crossover RCT of 41 men, 8 g of citrulline malate increased repetitions to fatigue by 52.92 % and reduced muscle soreness by 40 % compared with placebo, with mild stomach discomfort reported in 14.63 % of participants.Human studies · Randomized controlled trial