What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
L-citrulline benefits: where the science stands
For endurance: no.
Endurance is what most people take L-citrulline for, and the strongest evidence says it does not help: two combined reviews covering 12 trials; a trial of 48 people; two crossover trials, 35 people in all found no real difference. As of August 2026, the verdicts on this page rest on evidence from 137 trials, drawn from the strongest research among the 570 papers on PubMed that mention L-citrulline. Every claim is checked below.
570 papers on PubMed · evidence from 137 trials
Claim by claim
- EnduranceWell studied, and it does not work. The biggest review covered 9 trials.
- Blood pressureThe science is still forming. The best studies disagree.
- Blood sugarThe science is still forming. The best studies disagree.
- Energy and fatigueAlmost no real studies. Nothing clear so far.
See 9 more scored claims+
- HeartAlmost no real studies. What exists leans positive.
- LiverAlmost no real studies. Nothing clear so far.
- Muscle in older adultsThe science is still forming. The best studies disagree.
- Muscle sizeThe science is still forming. No real difference found so far.
- Performance and vitalityThe science is still forming. Results lean positive, but there is not much yet.
- PregnancyThe science is still forming. No real difference found so far.
- Sprint and repeated-effort powerAlmost no real studies. Nothing clear so far.
- Strength and powerThe science is still forming. The best studies disagree.
- Weight and body fatThe science is still forming. No real difference found so far.
Pairs people ask about
The 28 sources we read
- 2016Crossover trial · 10 people · no clear effect on sprint and repeated-effort powersource
- 2017Crossover trial · 25 people · no clear effect on blood pressuresource
- 2018Meta-analysis · pools 5 trials · no clear effect on blood pressuresource
- 2018Crossover trial · 26 people · no clear effect on endurancesource
- 2019Meta-analysis · pools 12 trials, 198 people · small benefit for strength and powersource
- 2019Crossover trial · 12 people · no clear effect on strength and powersource
- 2020Crossover trial · 9 people · no clear effect on endurancesource
- 2021Meta-analysis · pools 3 trials · no clear effect on endurancesource
- 2021Meta-analysis · pools 8 trials, 137 people · small benefit for strength and powersource
- 2021Randomized trial · 44 people · no clear effect on muscle in older adultssource
- 2022Randomized trial · 25 people · small benefit for blood pressuresource
- 2022Meta-analysis · pools 4 trials · no clear effect on strength and powersource
- 2023Meta-analysis · pools 9 trials, 158 people · no clear effect on endurancesource
- 2023Meta-analysis · pools 7 trials, 303 people · small benefit for muscle in older adultssource
- 2023Crossover trial · 14 people · no clear effect on energy and fatiguesource
- 2024Randomized trial · 36 people · no clear effect on blood pressuresource
- 2024Randomized trial · 20 people · no clear effect on blood pressuresource
- 2024Randomized trial · 48 people · no clear effect on endurancesource
- 2025Meta-analysis · pools 15 trials, 415 people · small benefit for blood pressuresource
- 2025Randomized trial · 33 people · no clear effect on strength and powersource
- 2025Crossover trial · 16 people · benefit for strength and powersource
- 2025Meta-analysis · pools 21 trials · no clear effect on muscle size; no clear effect on weight and body fatsource
- 2025Randomized trial · 44 people · no clear effect on liver; no clear effect on weight and body fatsource
- 2025Randomized trial · 115 people · no clear effect on pregnancysource
- 2025Randomized trial · 16 people · benefit for blood sugar; benefit for heartsource
- 2026Randomized trial · 43 people · no clear effect on weight and body fatsource
- 2026Meta-analysis · pools 6 trials · no clear effect on blood sugarsource
- 2026Meta-analysis · pools 30 trials, 644 people · small benefit for performance and vitalitysource
Chosen as the strongest evidence out of 570 papers on PubMed. Every row links to its paper.
Fair questions
Does L-citrulline work?+
For endurance, the strongest evidence says no. The biggest review covered 9 trials.
Is L-citrulline safe?+
No caution is recorded on this page. That is not a safety guarantee; the studies we read were not safety trials.
Why only 28 sources, when PubMed lists 570?+
The 570 is every paper that mentions L-citrulline in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 28 cover 137 trials between them, and every one is linked above. Both counts are measured, not estimated.