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
Selected research topic
Blood pressure and vascular health
Some measured outcomes improved in human comparison studies. Read these findings with their populations and conditions.
Findings from a combination study cannot be attributed to this ingredient alone.
Some findings concern patients or people with a deficiency.
- Publications for this topic
- 16
- Human comparison publications
- 2
- Publications needing review
- 12
Findings in the studies
Brachial artery flow-mediated dilation
- A better result than the comparison group was reported.
What the comparison group used was not confirmed.
Single ingredientMeasurement and study conditions
- Study type
- Randomized controlled trial: subjects were randomly assigned to groups for comparison.
- Study population
- Human participants · Participant characteristics were not confirmed.
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups.
- Measurement time
- Not confirmed.
diastolic blood pressure
- A better result than the comparison group was reported.
What the comparison group used was not confirmed.
Patient group · Single ingredientMeasurement and study conditions
- Study type
- Randomized controlled trial: subjects were randomly assigned to groups for comparison.
- Study population
- Human participants · Patient group
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups.
- Measurement time
- Not confirmed.
resting BP
Other human research, including observational studies and reviews
- A change was reported before and after use. Its cause cannot be isolated.
Several ingredients were tested together, so this ingredient’s individual effect is unknown.
General population · Combination studyMeasurement and study conditions
- Study type
- Randomized controlled trial: subjects were randomly assigned to groups for comparison.
- Study population
- Human participants · General population
- Ingredients tested
- Ingredient combination
- How results were compared
- Changes within the same group were compared. · Study comparison: within-subject crossover among citrulline malate, beetroot nitrate, and placebo
- Measurement time
- acute post-supplement and submaximal leg-extension protocol
SBP
Other human research, including observational studies and reviews
- A change was reported, but the comparison could not be confirmed.General population · Unspecified.
Measurement and study conditions
- Study type
- Meta-analysis
- Study population
- Human participants · General population
- Ingredients tested
- Unknown intervention
- How results were compared
- Study comparison: Pooled review/meta-analysis result as reported; abstract result sentence does not identify the compa
- Measurement time
- Unspecified.
This result is held for interpretation. That does not mean research found no effect.
Outcome groups needing additional review (6)
- atherogenic-endothelial protection · Distinct papers needing additional review: 1Evidence criteria check: 1
- blood pressure · Distinct papers needing additional review: 1Evidence criteria check: 1
- blood pressure regulation · Distinct papers needing additional review: 1Evidence criteria check: 1
- endothelial senescence · Distinct papers needing additional review: 1Evidence criteria check: 1
- FMD · Distinct papers needing additional review: 1Evidence criteria check: 1
- sfemFMD · 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.
Representative outcome and study details
Human studies reported between-group improvement in Brachial artery flow-mediated dilation.
Single-ingredient studies · Human studies · Population not specified · between-group comparison
1 publications linked to this result
- Route, form, dose, or population details are incomplete, so the findings cannot be confirmed as directly comparable.
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 16 · distinct papers 16 · papers with a confirmed human comparison 2 · papers needing additional review 12
A publication may appear in more than one count. These numbers should not be added. 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.
- atherogenic-endothelial protection: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- blood pressure: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- blood pressure regulation: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- Brachial artery flow-mediated dilation: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- diastolic blood pressure: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- endothelial senescence: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- FMD: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- resting BP: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- SBP: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- sfemFMD: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
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.
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.
No reviewed caution rules are available yet. Reported caution findings are shown below.
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