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Citrulline

  • Dietary supplement
  • Varies by country
  • Identity checked
  • Sources last checked 2026-09-04

This page shows what was measured, who it was measured in, and what that does not settle.

What Citrulline does in the body

RNAWiki has not recorded what this substance changes in the body.

What happened in people

RNAWiki has not yet published a reviewed conclusion for this use.

A fixed RNAWiki sentence

Where this came from

Wording RNAWiki always uses, not a finding about this substance.

No reviewed claim names a result for any goal on this record.

No source is stored against this line.

The limit that matters most

Not recorded.

Where it acts
Not recorded.
Kind of result
No result is published, so no kind of result applies yet
Supervision
Not usually supervised: sold as a supplement or food ingredient where recorded. That is a legal category, not a safety judgement.

What the registries record it as

  • The substance registry classes this as chemical.

    FDA substance registry · 29VT07BGDA · read 2026-08-29

  • The supplement label database classes it as amino acid, under the name L-Citrulline.

    NIH Dietary Supplement Label Database · 701 · read 2026-08-29

  • Its recorded molecular formula is C6H13N3O3, weighing 175.19.

    PubChem record · 9750 · read 2026-08-29

Where each sentence above came from

No plain explanation of what this changes is stored.

No recorded use is stored in reader language.

No statement of the main limit is recorded.

The four opening statements run to 26 words.

Words this page uses

Four words worth knowing first

Chosen from what this page shows, with each one explained before the word it depends on.

Stand-in result

A stand-in result is a number measured because the real result takes too long.

A picture of it, and where the picture fails

It is like judging a journey by the speedometer rather than by arriving.

Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.

What people get wrong. A stand-in result is often reported as the result itself.

A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.

Enzyme

An enzyme is a protein that speeds up one chemical change.

A picture of it, and where the picture fails

An enzyme is like a machine on a production line doing one cut.

Where that stops being true. A machine is switched on and off by a person. Enzymes are controlled by the cell.

What people get wrong. Enzymes are thought to be used up. They are not; they work again and again.

A catalytic protein that lowers the activation energy of a specific reaction.

Receptor

A receptor is a part of a cell that a signal fits into.

A picture of it, and where the picture fails

A receptor is like a lock waiting for one key.

Where that stops being true. A lock either opens or does not. A receptor can be half-triggered, or worn out.

What people get wrong. Fitting a receptor is read as causing a benefit. It causes a step, and nothing more.

A protein that binds a specific ligand and converts that binding into a cellular response.

Pathway

A pathway is a chain of steps inside a cell, each one setting off the next.

A picture of it, and where the picture fails

A pathway is like a row of dominoes.

Where that stops being true. Dominoes fall one way. Pathways loop back and can switch themselves off.

What people get wrong. Changing one step is read as changing the outcome. Other steps often absorb it.

An ordered series of molecular interactions producing a defined cellular change.

What happened in peopleRead from sources, not yet reviewed

What was measured, goal by goal

One row for each goal a registered study measured something for. One column for each kind of thing that could be measured.

Registered studies list 40 outcome measures that RNAWiki could read. A registered study says what someone planned to measure. It does not say what they found. 0 of the matched studies tested this substance, and 0 posted a result.

There is no single score. A strong test result and a weak life result are different facts.

Goals down the side, kinds of measurement across the top. Each cell says what kind of thing was registered, not what was found.
GoalLife outcomeWhat a body can doHow a person feelsA test resultA step in the bodyHarmsHow longWho was studied
Fertility and sexual healthNothing in the sources checkedNo registered study lists a life outcome for this goal.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Nothing in the sources checkedNo registered study lists a symptom measure for this goal.Nothing in the sources checkedNo registered study lists a test result for this goal.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
PainNothing in the sources checkedNo registered study lists a life outcome for this goal.Nothing in the sources checkedNo registered study lists a performance measure for this goal.Waiting for a reviewer1 registered symptom measure.Nothing in the sources checkedNo registered study lists a test result for this goal.Nothing in the sources checkedNo registered study lists a body-step measure for this goal.Not recordedHarms were not a registered measure for this goal.Not recordedNo finished study window is recorded.Waiting for a reviewerWho was studied is listed further down the page.
Which registered measures put each goal on this table
Fertility and sexual health
testosterone; testosterone to cortisol
Pain
visual analogue scale pain

Sorted by fixed word lists, version v1. A name the rules do not recognise stays unsorted rather than moving to the nearest column.

What each mark on this table means
Nothing in the sources checked
No registered study lists a life outcome for this goal.
Not recorded
Harms were not a registered measure for this goal.
Waiting for a reviewer
Who was studied is listed further down the page.

What happened in peopleRead from sources, not yet reviewed

What happened in people

Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.

Fat Mass

The study did not show it

Who was studied
NCT04630977
How many people
3000
Study design
Not applicable
Compared against
Not recorded for this study
Kind of result
Measured performance
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route.

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • NIH Dietary Supplement Label Database · a recorded source, not a stored snapshot
  • Europe PMC · a recorded source, not a stored snapshot

Adverse pregnancy outcome

The study did not show it

Who was studied
NCT05934318
How many people
2960
Study design
Not applicable
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route.

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • NIH Dietary Supplement Label Database · a recorded source, not a stored snapshot
  • Europe PMC · a recorded source, not a stored snapshot

Adverse disease outcome

The study did not show it

Who was studied
NCT06426147
How many people
2200
Study design
Not applicable
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route.

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • NIH Dietary Supplement Label Database · a recorded source, not a stored snapshot
  • Europe PMC · a recorded source, not a stored snapshot

The remission rate of gastrointestinal dysfunction

The study did not show it

Who was studied
NCT03048903
How many people
400
Study design
Phase 2
Compared against
Not recorded for this study
Kind of result
What a body can do day to day
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route.

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • NIH Dietary Supplement Label Database · a recorded source, not a stored snapshot
  • Europe PMC · a recorded source, not a stored snapshot

Change in linear growth based on absolute height gain over 3 months intervention period

The study did not show it

Who was studied
NCT06739629
How many people
342
Study design
Not applicable
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route.

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • NIH Dietary Supplement Label Database · a recorded source, not a stored snapshot
  • Europe PMC · a recorded source, not a stored snapshot

Incidence of pregnancy induced hypertension

The study did not show it

Who was studied
NCT04979793
How many people
338
Study design
Phase 1
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route.

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • NIH Dietary Supplement Label Database · a recorded source, not a stored snapshot
  • Europe PMC · a recorded source, not a stored snapshot
What we know
RNAWiki holds 6 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.

What happened in peopleRead from sources, not yet reviewed

How close this is to real life

The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.

  1. Living longer, or avoiding a major event No evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
  2. What a body can do day to day No evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
  3. Measured performance No evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
  4. Symptoms and quality of life Evidence recorded. Pain, tiredness, mood, sleep, as the person rated it.2 registered measures of this kind.
  5. A number that stands in for health Evidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.8 registered measures of this kind.
  6. A step measured inside a person Evidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
  7. Animals Evidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in C. elegans (roundworm), Mouse, Rat. A result in animals says what to test next. It does not say what happens in people.
  8. Cells in a dish Evidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
  9. A guess from software No evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.

Higher on these steps means closer to something a person would feel. It does not mean better done.

What it would be like to takeRead from sources, not yet reviewed

Felt, measured, or meaningful

Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.

Felt

Things a person could notice without a test.

  • asthma control questionnaire
  • visual analogue scale pain

Measured

Things only a test, a scale or a device shows.

  • blood pressure
  • aortic blood pressure
  • ambulatorial blood pressure monitoring
  • systolic blood pressure
  • diastolic blood pressure
  • blood pressure control during the cold pressor test
  • flow mediated dilation
  • creatinine

Meaningful

Things that change how a life goes, not only a number.

No registered study measured anything of this kind.

A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.

Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.

Measured, but not felt. A number moves. The person notices nothing. Both can be true.

Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.

Matters, but takes years. The result that counts may take longer than anyone would keep watching.

Names that fit none of the three (30)
  • gi perfusion
  • gut damage
  • microcirculation
  • exhaled nitric oxide
  • myofibrillar fractional synthetic rate
  • claudication distance
  • volume of distribution
  • treatment related adverse events as assessed by ctcae v4 0
  • reactive hyperemic index
  • blood flow
  • vascular function
  • arginine production
  • asthma control test
  • sofa
  • arterial pressure
  • endothelial function
  • arterial stiffness
  • arginine bioavailability
  • reactive hyperemia
  • muscle hyperemia

These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.

What is missing or unclearRead from sources, not yet reviewed

Were people like you studied?

RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.

Who was studied

No description of who was studied is recorded.

Who is missing from the studies

  • Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

Where the result stopped carrying

  • This is a scope explorer, not a diagnosis engine.
  • It shows who was studied so you can see whether people similar to you were included.

RNAWiki cannot tell whether a study fits you. It can show who was in it.

What it would be like to takeRead from sources, not yet reviewed

Why it might seem to do nothing

A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.

It was studied for a different goal

The studies measured something else entirely.

On this record: Some registered studies measured things that match no goal on this page.

It was studied in different people

The people in the studies were not much like the reader.

On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

The evidence may simply be wrong

Small early studies often do not hold up.

On this record: RNAWiki has not yet published a reviewed conclusion for this use.

Other reasons RNAWiki checked and found nothing for (10)
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.

None of these is a reason to take more. Taking more is not a step this page ever suggests.

What it would be like to takeRead from sources, not yet reviewed

What taking it involves

The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.

How it is supplied

Varies by country

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

Read from the recorded approval status.

No source is stored against this line.

Form and route

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

No form or route is recorded.

No source is stored against this line.

Who oversees it

Not usually supervised: sold as a supplement or food ingredient where recorded. That is a legal category, not a safety judgement.

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

The identity record classes it as a supplement ingredient; no medicines register records an approval.

No source is stored against this line.

What is in the pack

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

Nothing is recorded about product quality.

No source is stored against this line.

Where it is registered

Regulatory records are listed in the technical disclosure at the foot of this page.

Counted from records

Where this came from

A count of rows RNAWiki holds. It describes our records, not your body.

Register entries are stored per jurisdiction and shown with their dates.

No source is stored against this line.

Why people stop

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

No record of why people stopped taking it is stored for this substance.

No source is stored against this line.

What it would be like to takeNothing found in the sources checked

What can go wrong

Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.

Nothing found in the sources checked

No harm is recorded against this substance in the sources RNAWiki checked. Finding nothing is not the same as showing there is nothing.

The sources listed were searched and held nothing. That is not the same as nothing existing.

Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.

Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

What is missing or unclearRead from sources, not yet reviewed

Does the exact form matter?

Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.

The form that was studied

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

The exact form studied is not recorded.

No source is stored against this line.

What is sold

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

Nothing further is recorded about which forms are sold.

No source is stored against this line.

What is recorded as being sold

  • 1676 marketed supplement labels list this ingredient, classed as amino acid/protein.

    NIH Dietary Supplement Label Database · 14874 · read 2026-08-29

  • Those labels carry all other, nutrient and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.

    NIH Dietary Supplement Label Database · 14874 · read 2026-08-29

Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.

What it would be like to takeRead from sources, not yet reviewed

What you could measure

Watching one thing carefully can tell you whether it moved. It cannot tell you what moved it.

This is sold without a prescription, so a person can sensibly watch one thing and see whether it moves.

  1. Pick one goal. One goal only. Two at once cannot be told apart afterwards.

  2. Pick one thing to watch. Registered studies measured things like: blood pressure; aortic blood pressure; ambulatorial blood pressure monitoring.

  3. Measure before you start. Take the same measurement several times first. One reading is not a starting point.

  4. Know the swing. Write down how much it moves on its own across a normal week.

  5. Change one thing. Change nothing else at the same time, including training and sleep.

  6. Give it the study length. No finished study window is recorded, so no length is suggested here.

  7. Track whether you took it. Missed days are the most common reason a home test shows nothing.

  8. Read the trend. Look at the line across weeks. A single reading tells you almost nothing.

What not to measure

  • Anything that swings more day to day than the change you are looking for.
  • A wearable estimate of sleep stages, which is an estimate and not a measurement.
  • Weight on one morning, which mostly records water.
  • A feeling you did not write down before starting, such as: asthma control questionnaire.

When to stop

  • Stop if something new and unpleasant starts, and ask a pharmacist or doctor.
  • Stop if you cannot keep everything else steady, because the result will not mean anything.
  • Stop at the end of the window you set, and read the trend then.

Tracking can show whether something changed for you. It cannot show what caused it.

RNAWiki does not work out an amount for anyone.

What is missing or unclearRead from sources, not yet reviewed

What nobody knows yet

Open questions, each with why it is open and what would close it.

How fast does the body clear it?

The sources RNAWiki checked hold nothing for this field.

Why it matters. Without this, nothing on this page can say how long anything lasts.

What would answer it

A stored source that records it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing populations

Which groups were under-represented in the studies has not been recorded.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing long-term data

No completed tested study window is recorded.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

No reviewed conclusion

RNAWiki has not yet published a reviewed conclusion for this use.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing interaction studies

No interaction was found in the registers checked. Not finding one is not the same as showing there is none.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Formulation uncertainty

Several salts, forms or products of Citrulline are recorded. Results from one form may not transfer to another.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Mechanism not reviewed

No reviewed mechanism story exists for this substance.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

What happened in peopleRead from sources, not yet reviewed

Check any of this yourself

Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.

Where else this substance is registered

FDA substance identifier (UNII)
29VT07BGDA
CAS registry number
372-75-8
PubChem compound
9750
ChEBI
16349
RxNorm concept
2567
EMA substance identifier
100000080134
European Chemicals Agency number
206-759-6
DrugBank
DB00155

Checks this page had to pass

  • Passed

    Identity resolved

    no open identity hold

  • Passed

    No unresolved merge across substance families

    no quarantine open

  • Not passed

    Every public sentence names a source

    The opening statement carries no source: the record holds neither an explanation nor a recorded use.

  • Not passed

    Trial roles classified for highlighted evidence

    No registered study is classified as testing this substance.

  • Passed

    No internal keys in reader text

    enforced by the copy-contract test over the rendered page

  • Passed

    Safety mode resolved

    The identity record classes it as a supplement ingredient; no medicines register records an approval.

  • Passed

    Canonical metadata present

    slug and display name present

What is missing or unclearRead from sources, not yet reviewed

What to learn next

Ordered by what would most change how you read this page, starting with what is easiest to misunderstand.

This order is fixed in code and does not count clicks or time on the page.

What is not here

7 questions this page could not answer

These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.

  • The path through the body — found nothing in the sources checked.
  • How long anything takes — found nothing in the sources checked.
  • What it may clash with — found nothing in the sources checked.
  • Other ways to the same goal — found nothing in the sources checked.
  • Claims that go past the evidence — found nothing in the sources checked.
  • How this medicine reached us — found nothing in the sources checked.
  • What changed on this page — found nothing in the sources checked.

The record as stored

The full record, for auditing

Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.

Recorded evidence blocks (11)

What did Citrulline's largest trial (2960 people) and its longest (9.4 years) measure?


2960 people in Citrulline's largest registered study, 9.4 years in its longest registered window, measuring Peak plasma citrulline concentration (Cmax). ClinicalTrials.gov · 2026-09-01

31 na, 14 phase1, 13 phase2, 6 phase3, 2 early phase1, 1 phase4; NCT06312748; 2030-09-30. Last human test completed 2024, NCT05722860.

Interpretation These counts include studies where Citrulline was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.

Show the evidence
  • na
    31
  • phase1
    14
  • phase2
    13
  • phase3
    6
  • early phase1
    2
  • phase4
    1
1 more recorded row
  • Last recorded human test NCT05722860
    2024-12-28

recorded 2026-09-01 · last checked 2026-09-04

From C. elegans to human: where has Citrulline shown lifespan?


C. elegans: healthspan, mouse: lifespan, rat: mechanism-only and human: biomarker (61): the rungs where Citrulline has a recorded finding. Europe PMC and ClinicalTrials.gov · organism ladder · 2026-09-01

Interpretation Peak plasma citrulline concentration (Cmax) — the recorded outcome words.

Yeast C. elegans healthspanDrosophila Mouse lifespanRat mechanism-onlyDog Non-human primate Human biomarker
Show the evidence
  • C. elegans
    healthspan
  • mouse
    lifespan
  • rat
    mechanism-only
  • human NCT02659644
    biomarker; Peak plasma citrulline concentration (Cmax); 61

recorded 2026-09-01 · last checked 2026-09-04

7 of Citrulline's trials stopped: futility/efficacy, accrual/recruitment, funding/business, other?


futility/efficacy (1), accrual/recruitment (1), funding/business (1) and other (4): Citrulline's stop wording, clustered. ClinicalTrials.gov · 2026-09-01

"Principal Investigator moved to another institution"; 7 of 61 registered studies

Show the evidence

Trial

  • NCT02659644
    withdrawn; "Principal Investigator moved to another institution"
  • NCT02772887
    terminated; "Inability to successfully recruit study participants"
  • NCT03542812
    terminated; "The study stopped enrollment prior to the initially projected 18 subjects per phase due to lack of funding to continue to recertify the drug and because an adequate number of subjects were enrolled for each phase to analyze…"
  • NCT04770155
    terminated; "Despite significant effort, we were unable to obtain the supply of drugs and supplements needed for the various arms of this Clinical Trial."
  • NCT04852172
    terminated; "Impacted by viraemia resulting in higher than expected admissions"
  • NCT04979793
    suspended; "At the request of the PI"
  • 1 further recorded trial NCT05253209
    terminated; "Interim Analysis triggered futility"

recorded 2026-09-01 · last checked 2026-09-04

Human studies of Citrulline used L-citrulline tablets, 1000 mg — over how long?


Human studies of Citrulline used "L-citrulline tablets, 1000 mg". ClinicalTrials.gov · 2026-09-01

4 recorded entries; human; capsule; also "2 weeks of L-citrulline supplementation (6g/day).", "L-citrulline (750 mg/capsule)", "L-citrulline 3 g"

Show the evidence

human

  • NCT00343954
    L-citrulline tablets, 1000 mg
  • NCT02104375
    2 weeks of L-citrulline supplementation (6g/day).
  • NCT02214290
    capsule; L-citrulline (750 mg/capsule)
  • NCT04770155
    L-citrulline 3 g

recorded 2026-09-01 · last checked 2026-09-04

Could one person measure Citrulline's effect on gi perfusion?


Gi perfusion: measured in Citrulline's trials.

Interpretation gi perfusion is the recorded endpoint.

Show the evidence

biomarkers

  • gi perfusion; 2026-09-01
  • gut damage; 2026-09-01
  • microcirculation; 2026-09-01
  • blood pressure; 2026-09-01
  • exhaled nitric oxide; 2026-09-01
  • aortic blood pressure; 2026-09-01
14 more recorded rows
  • biomarkers
    myofibrillar fractional synthetic rate; 2026-09-01
  • biomarkers
    claudication distance; 2026-09-01
  • biomarkers
    volume of distribution; 2026-09-01
  • biomarkers
    treatment related adverse events as assessed by ctcae v4 0; 2026-09-01
  • biomarkers
    reactive hyperemic index; 2026-09-01
  • biomarkers
    blood flow; 2026-09-01
  • biomarkers
    vascular function; 2026-09-01
  • biomarkers
    ambulatorial blood pressure monitoring; 2026-09-01
  • biomarkers
    arginine production; 2026-09-01
  • biomarkers
    asthma control questionnaire; 2026-09-01
  • biomarkers
    asthma control test; 2026-09-01
  • biomarkers
    sofa; 2026-09-01
  • biomarkers
    systolic blood pressure; 2026-09-01
  • biomarkers
    diastolic blood pressure; 2026-09-01
  • human trials at or under30
    28
  • Not recorded for this substance
    a recorded half-life
  • smallest human trial
    0; NCT02659644; PHASE1; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; WITHDRAWN

Which of adverse pregnancy outcome, ambulatorial blood pressure monitoring and aortic blood pressure did Citrulline's trials measure?


adverse pregnancy outcome, ambulatorial blood pressure monitoring and aortic blood pressure lead 40 outcome terms across Citrulline's trials. ClinicalTrials.gov · 2026-09-01

Interpretation blood pressure, exhaled nitric oxide, aortic blood pressure, myofibrillar fractional synthetic rate, claudication distance and volume of distribution follow.

Show the evidence
  • gi perfusion
    1
  • gut damage
    1
  • microcirculation
    1
  • blood pressure
    1
  • exhaled nitric oxide
    1
  • aortic blood pressure
    1
14 more recorded rows
  • myofibrillar fractional synthetic rate
    1
  • claudication distance
    1
  • volume of distribution
    1
  • treatment related adverse events as assessed by ctcae v4 0
    1
  • reactive hyperemic index
    1
  • blood flow
    1
  • vascular function
    1
  • ambulatorial blood pressure monitoring
    1
  • arginine production
    1
  • asthma control questionnaire
    1
  • asthma control test
    1
  • sofa
    1
  • systolic blood pressure
    1
  • diastolic blood pressure
    1

recorded 2026-09-01 · last checked 2026-09-04

Which of Citrulline's 11 ongoing trials reports first?


11 registered trials of Citrulline are open; earliest completion 2026-06-30. ClinicalTrials.gov · 2026-09-01

Change in Asthma Control Questionnaire; Safety of oral L-Citrulline administration; latest 2030-09-30

Show the evidence

Trial

  • NCT03885245
    "Supplementing L-citrulline to Overweight Late Asthma oNset Phenotypes"; n 60; "Change in Asthma Control Questionnaire"; 2026-06-30
  • NCT05259904
    "Study to Improve Deployment Related Asthma by Using L-Citrulline Supplementation"; n 75; "Change in Asthma Control Questionnaire"; 2028-10
  • NCT05636397
    "Safety and PK-PD Study of Oral L-CIT in Preterm Infants With BPD±PH and NEC"; n 36; "Safety of oral L-Citrulline administration"; 2028-03
  • NCT05934318
    "L-ArGinine to pRevent advErse prEgnancy Outcomes (AGREE)"; n 2960; "Adverse pregnancy outcome"; 2026-12-30
  • NCT06212765
    "Oral Citrulline Supplementation in COPD Patients With Malnutrition"; n 60; "Fat Free Mass Index"; 2026-09-25
  • NCT06312748
    "Novel Approaches for Improving Vascular Function in Veterans With HFpEF"; n 90; "Flow-mediated dilation (FMD)"; 2030-09-30
5 further recorded trials
  • NCT06426147
    "L-citrulline to Improve Adverse Outcomes in Admitted Children (EChiLiBRiST, Clinical Trial 2, Inpatients)"; n 2200; "Adverse disease outcome"; 2027-08-01
  • NCT06635902
    "Intravenous L-Citrulline for Vaso-occlusive Pain Episode in Sickle Cell Disease"; n 99; "Time-to-crisis resolution"; 2029-03
  • NCT06989567
    "A Study of Intravenous L-Citrulline in Patients Aged 6-21 Years Old With Sickle Cell Disease Presenting to Emergency Departments in Acute Vaso-Occlusive Crisis"; n 120; "Change in pain score from baseline to discharge"; 2029-06
  • NCT07617909
    "L-Citrulline Versus Tamsulosin for Medical Expulsive Therapy of Distal Ureteral Stones"; n 120; "Stone Expulsion Rate Within 4 Weeks"; 2026-11
  • NCT07642505
    "L-Citrulline and Tadalafil for Mild to Moderate Erectile Dysfunction"; n 133; "Change in International Index of Erectile Function-Erectile Function Domain Score"; 2026-12

recorded 2026-09-01 · last checked 2026-09-04

Which 31 trials of Citrulline posted no result?


Posted no result
31 of 31 completed trials
Registrations
NCT00223730, NCT00756080, NCT00201214, NCT00335244, NCT00950976 and NCT01462591, and 25 more
Completion dates
oldest 2007-12; newest 2024-07-01
Show the evidence

Trial

  • NCT00223730
    2007-12
  • NCT00756080
    2009-01
  • NCT00201214
    2009-12
  • NCT00335244
    2009-12
  • NCT00950976
    2010-08
  • NCT01462591
    2012-05
14 further recorded trials
  • NCT00714675
    2013-01
  • NCT00743210
    2013-06
  • NCT02315391
    2013-12
  • NCT01599676
    2014-12
  • NCT02104375
    2014-12
  • NCT01715844
    2017-06-01
  • NCT03127917
    2017-12-31
  • NCT02417428
    2018-12
  • NCT02943161
    2019-03-31
  • NCT02809170
    2019-06
  • NCT02521220
    2019-08-30
  • NCT02864017
    2020-04
  • NCT02801695
    2020-12-01
  • NCT04404426
    2021-05-28

At the median, Citrulline's trials enrolled 36 people — anything larger?


Median enrolment
36
Largest enrolment
2960
Registered trials counted
61

Was Citrulline studied with fasting and exercise?


fasting and exercise are named in Citrulline's label sentences: "Although L-citrulline (CIT) supplementation improves endothelial function in older women and decreases fasting glucose in those with T2DM, whether it improves vascular function and blood glucose during acute hyperglycemic states in T2DM is unknown. <b>Methods:</b> We randomized 16 patients with…" openfda-label+europepmc · 2026-05-19

2 recorded statements; fasting, exercise

Show the evidence
  • fasting
    Although L-citrulline (CIT) supplementation improves endothelial function in older women and decreases fasting glucose in those with T2DM, whether it improves vascular function and blood glucose during acute hyperglycemic states in T2DM is unknown. <b>Methods:</b> We randomized 16 patients with T2DM (age 62 ± 6 years) to consume either CIT (6 g/day) or placebo for 4 weeks.
  • exercise
    This pilot randomized controlled trial examined whether short-term (6-week) citrulline malate (CM) supplementation combined with multicomponent exercise could improve physical function, metabolic biomarkers, and quality of life in physically active older women.

recorded 2026-05-19 · last checked 2026-09-04

What is recorded about Citrulline and AMPK?


"This was achieved through the regulation of key metabolites (e.g., L-ornithine, L-citrulline, and fumaric acid) and key targets (Abcg8, Ctsk, Ciapin1, and Esr1), and activation of the ESR1/AMPK and LKB1/AMPK signaling pathways." — where Citrulline and AMPK appear together. Europe PMC · pathway abstract search · 2026-08-25

AMPK, IGF-1, autophagy, mTOR; PMID 42642007, 40452593, 41938116, 40053596

Show the evidence
  • AMPK PMID 42642007
    "This was achieved through the regulation of key metabolites (e.g., L-ornithine, L-citrulline, and fumaric acid) and key targets (Abcg8, Ctsk, Ciapin1, and Esr1), and activation of the ESR1/AMPK and LKB1/AMPK signaling pathways."

IGF-1

  • PMID 40452593
    "Results from IGF-1 siRNA experiments indicate that part of the L-citrulline effects on gene expression was dependent on IGF-1."
  • PMID 40452593
    "L-citrulline supplementation improves the IGF-1 signaling pathway in preeclampsia, at least partly, via polyamine production."
  • autophagy PMID 41938116
    "Particular emphasis is placed on the multifaceted protective role of L-citrulline, which acts through synergistic mechanisms involving modulation of the arginine-nitric oxide (NO) pathway, preservation of mitochondrial homeostasis, restoration of autophagy flux, and suppression of apoptotic signaling."
  • mTOR PMID 40053596
    "Mechanistically, citrulline served as a potential inhibitor of mammalian target of rapamycin (mTOR) activation in macrophage and regulated the mTOR-hypoxia-inducible factor 1α-glycolysis signaling pathway to counter inflammation and aging."
  • autophagy
    "Metabolomics analysis revealed that activation of autophagy by DR significantly alleviated the glutamate, aspartate n-acetyl-l-glutamate, ornithine, argininosuccinate, and citrulline levels in the liver induced by CAS."

recorded 2026-08-25 · last checked 2026-09-04

Where it is registered
Identifiers, relations and other names

The exact record

ChEMBL id
CHEMBL4297667
PubChem CID
162762
CAS number
70796-17-7
RxCUI
2567
InChIKey
RHGKLRLOHDJJDR-BYPYZUCNSA-N
Also called
Citrulline malate
Also called
L-citrulline dl-malate, L-citrulline malate, Stimol, L-CITRULLINE, turnobi, Citrulline Nitrate, CITRULLINE [MART.], CITRULLINE [MI], CITRULLINE [VANDF], Citrulline [WHO-DD], L-CITRULLINE [USP-RS]
Development code
NSC-27425
Trade name
Sold as citrulline malate 2:1 or 1:1, and as plain L-citrulline, Vascuflow
Component
Citrulline malate
Sources (9)

Sources

  • ClinicalTrials.gov clinicaltrials.gov ·
  • ClinicalTrials.gov ClinicalTrials.gov API v2 snapshot 2026-09-01T09:00:05 ·
  • this record's own fields 2,3,5 ·
  • Europe PMC dose-response search ·
  • Europe PMC pathway abstract search ·
  • Europe PMC search ·
3 more sources

ClinicalTrials.gov — US Government work · Europe PMC — metadata only, under the recorded legal gate · derived from this page's own recorded fields; no external licence · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work

How these records are assembled · Which registers were checked

Index-quality checks
  • identity passed: no open identity hold
  • required summary fields resolved: 3 required field(s) not terminal: Best-supported result, Biggest unanswered question, Human evidence
  • public claims reviewed: 0 reviewed claim(s); drafts are never rendered
  • source coverage passed: 9 source rows
  • no critical contamination: no quarantine open
  • canonical metadata passed: slug and display name present
  • no raw internal fields: enforced by the copy-contract test over the rendered page

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