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Lci9.0
L-Citrulline Research
Likely helpsModerate safety
45 peer-reviewed studies
What the evidence says
Likely helps
L-Citrulline appears to help in 7 of 9 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2010–2026 with a typical study size of 25 participants.
Based on 45 studies · 8 meta-analyses · 30 RCTs · 886,165 total participants
Confidence
High
What the studies found
7helped2unclear· 36 more without graded effect data
By outcome
Heart & blood pressureReduces blood pressure via sustained nitric oxide production · 4-8 weeks
Likely helps41 studies
Endurance & exercise performanceImproved endurance and reduced fatigue · 1-2 weeks consistent use · Increases NO availability and exercise tolerance · 30-60 minutes
Mostly mechanism / observational15 studies
RecoveryUp to 40% reduction in muscle soreness · 24-48 hours post-exercise
Lean body mass & muscle growthMay improve high-rep performance · 1-2 weeks
Mostly mechanism / observational4 studies
Glucose & metabolic
Mostly mechanism / observational3 studies
Cholesterol & lipidsReduces blood pressure via sustained nitric oxide production · 4-8 weeks
Too few graded studies2 studies
Therapeutic & clinical
Too few graded studies2 studies
Inflammation
Too few graded studies1 study
Men's vitalityImproved erectile function via nitric oxide · 2-4 weeks
Too few graded studies1 study
Safety profile
Too few graded studies1 study
By the numbers
Pulled from 25 studies with measurable effects
Likely real effects
58%
across studies
People studied
886k
typical study: 25 people
Strongest designs
38
8 pooled, 30 randomised
Showed benefit
67%
6/9 studies
How long studies ran
1–4 weeks
4
1–3 months
4
Populations Studied
General population2
Hypertensive postmenopausal women2
Athletes/exercising individuals1
Middle-aged and elderly individuals1
Active research area
37 studies in the last 5 years · Latest meta-analysis: 2026
201020182026
1Oxidative stress after exerciseMeta-AnalysisCited 3×n=1,080 · large study2023
In conclusion, our systematic review and meta-analysis found that L-Citrulline and L-Arginine did not influence inflammatory biomarkers and oxidative stress after exercise.
Porto AA et al. · Nutrients (2023)
No clear effect
← WorseNo effectBetter →
Could be chance
We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%.
In the sub-group "L-Arginine" we found a subtotal = -0.29 [-0.71, 0.12], p = 0.16, and heterogeneity = 0%.
No differences were observed between groups (p = 0.47), and I² = 0%) or in antioxidant activity (subtotal = -0.28 [-1.65, 1.08], p = 0.68, and heterogeneity = 0%).
3Systolic blood pressureMeta-AnalysisCited 2×n=415 · medium study2025
l-citrulline supplementation and watermelon intake overall lowered BP in middle-aged and elderly individuals.
Luo P et al. · Clinical nutrition ESPEN (2025)
Noticeable benefit
← WorseNo effectBetter →
Likely real
The results indicate that l-citrulline supplementation and watermelon intake significantly reduced SBP (-4.02 mmHg [95 % CI: -6.54 to -1.50], P = 0.002) and DBP (-2.54 mmHg [95 % CI: -4.27 to -0.81], P = 0.004) in the elderly.
Subgroup analysis showed that the combined supplementation of l-citrulline and l-arginine significantly decreased SBP (-10.44 mmHg [95 % CI: -13.57 to -7.31], P < 0.00001) and DBP (-4.86 mmHg [95 % CI: -7.93 to -1.79], P = 0.002) in this population.
l-citrulline supplementation and watermelon intake overall lowered BP in middle-aged and elderly individuals.
CIT supplementation appears to have no overall effect on body composition.
Ashtary-Larky D et al. · Nutrients (2025)
Overall, CIT supplementation had no substantial effects on body mass index (BMI), body weight, fat mass (FM), waist circumference (WC), body fat percentage (BFP), and fat-free mass (FFM).
Interventions lasting 3 to 8 weeks were associated with a significant increase in FFM.
CIT supplementation appears to have no overall effect on body composition.
6Post-exercise rating of perceived exertionMeta-AnalysisCited 33×n=206 · medium study2020
Citrulline supplements significantly reduced post-exercise RPE and muscle soreness without affecting blood lactate levels.
Rhim HC et al. · Journal of sport and health science (2020)
Likely real
Citrulline supplementation significantly reduced RPE (n = 7, p = 0.03) and muscle soreness 24-h and 48-h after post-exercise (n = 7, p = 0.04; n = 6, p = 0.25, respectively).
However, citrulline supplementation did not significantly reduce muscle soreness 72-h post-exercise (n = 4, p = 0.62) or lower blood lactate levels (n = 8, p = 0.17).
Given the positive effects observed from some investigations, future studies should continue to investigate the effects of both acute and chronic supplementation with L-citrulline and citrulline malate on markers of blood flow and exercise performance and should seek to elucidate the mechanism underlying such effects.
Gonzalez AM et al. · Journal of strength and conditioning research (2020)
Oral L-citrulline and citrulline malate supplementation have shown to increase plasma citrulline and arginine concentrations, along with total nitrate and nitrite concentrations.
Although blood flow enhancement is a proposed mechanism for the ergogenic potential of L-citrulline, evidence supporting acute improvements in vasodilation and skeletal muscle tissue perfusion after supplementation is scarce and inconsistent.
Nevertheless, several studies have reported that L-citrulline supplementation can enhance exercise performance and recovery.
10Physical performanceSystematic ReviewCited 11×n=19 · very small study2019
However, there is not enough evidence to establish a beneficial L-citr dosage for physical performance.
Huerta Ojeda Á et al. · Nutricion hospitalaria (2019)
All articles using a supplementation protocol with these amino acids, separately or in groups, were selected.
Results: a total of 38 articles were found, which were stratified according to the established protocol: a) supplementation with L-arg (n = 19); b) supplementation with L-arg and L-citr (n = 1); and c) supplementation with L-citr (n = 18), whether of short or prolonged duration.
Conclusion: there is evidence that L-citr works better as ergogenic than L-arg does on physical performance, since L-citr showed a positive effect on the rate of perceived exertion and muscular pain, in addition to a decrease in lactate concentrations and time in maximum tests.
This trial was registered at ClinicalTrials.gov (No. NCT05183893).
Martín-Olmedo JJ et al. · International journal of sport nutrition and exercise metabolism (2025)
CIT and CMA supplementation did not enhance maximal neuromuscular performance (all p ≥ .061, ηp2≤.066), or ballistic strength (all p ≥ .348, ηp2≤.025).
In conclusion, CIT and CMA supplementation may not increase the neuromuscular performance during low- to moderate-volume resistance training sessions in young, trained adults.
This trial was registered at ClinicalTrials.gov (No. NCT05183893).
12Upper body muscular enduranceRCTCited 1×n=33 · small study2025
Chronic citrulline supplementation seems to enhance upper body muscular endurance and post-exercise NOX response to RT, but there is no apparent difference between LC and CM in these aspects.
Bayat D et al. · Journal of the International Society of Sports Nutrition (2025)
Chronic citrulline supplementation seems to enhance upper body muscular endurance and post-exercise NOX response to RT, but there is no apparent difference between LC and CM in these aspects.
13Basketball players' performanceRCTCited 9×n=8 · very small study2025
Our findings indicate that short-term supplementation with Cr, BA, and L-Cit, as well as a combination of them during SSIT, can significantly improve the physical and physiological performance of basketball players compared to a PL.
Li M et al. · International journal of sports physiology and performance (2025)
Borderline
All training groups (Cr, BA, L-Cit, combined, and PL) showed significant improvements in physical and physiological performance over the 4-week intervention (P < .05).
14Athletic performance and vasodilationRCTCited 1×2025
Given the small sample size, this study serves as a pilot, and further research is needed to validate these findings on a larger scale.
Mollace R et al. · Nutrients (2025)
No harmful adverse effects were observed.
Max supplementation, providing beneficial effects on the antioxidant state and preserving the vascular endothelium might be a supplementation strategy to improve athletic performance and potentiate results.
Given the small sample size, this study serves as a pilot, and further research is needed to validate these findings on a larger scale.
15Glucose homeostasis in type 2 diabetesRCTCited 25×n=54 · small study2021
In conclusion, L-citrulline supplementation might improve glucose homeostasis, some lipid factors and inflammatory markers in overweight and obese patients with T2D.
Azizi S et al. · Phytotherapy research : PTR (2021)
Moreover, no significant inter- and intra-group changes were observed for dietary intakes, anthropometric indices, total and low-density lipoprotein cholesterol levels (p > .05).
In conclusion, L-citrulline supplementation might improve glucose homeostasis, some lipid factors and inflammatory markers in overweight and obese patients with T2D.
The combination of BCAAs, L-citrulline, and A-GPC used in this study improves cycling performance and may be useful for individuals seeking to improve athletic performance, particularly in disciplines requiring lower body muscular strength and endurance.
Harrington RN · Journal of the International Society of Sports Nutrition (2023)
With the test supplement, there was an average increase in TT peak power of 11% and an average increase in time to fatigue of 36.2% in the HIEC test compared to the placebo.
There was no significant improvement in time to completion, average power, OMNI rating of perceived exertion, or VAS responses on perceived exertion in the TT test and no significant improvement in VAS measures of perceived exertion in the HIEC test.
The combination of BCAAs, L-citrulline, and A-GPC used in this study improves cycling performance and may be useful for individuals seeking to improve athletic performance, particularly in disciplines requiring lower body muscular strength and endurance.
Ormesher L et al. · Reproductive sciences (Thousand Oaks, Calif.) (2024)
No clear effect
← WorseNo effectBetter →
L-citrulline had no effect on diastolic BP (L-citrulline: - 1.82 95% CI (- 5.86, 2.22) vs placebo: - 5.00 95% CI (- 12.76, 2.76)), uterine artery Doppler or angiogenic biomarkers.
Although there was no effect on BP, retrospectively, this study was underpowered to detect BP changes < 9 mmHg, limiting the conclusions about biological effects.
Acute ingestion of SPB after eight days may enhance blood flow, L-citrulline, and L-arginine plasma concentrations after high-intensity exercise, which may enhance performance.
Cabre HE et al. · Journal of the International Society of Sports Nutrition (2023)
Acute ingestion of SPB after eight days may enhance blood flow, L-citrulline, and L-arginine plasma concentrations after high-intensity exercise, which may enhance performance.
19Exhaled nitric oxideRCTCited 2×n=14 · very small study2023
In the present study, although short-term L-citrulline supplementation increased exhaled NO•, no ergogenic aids were found on the examined parameters at rest and after resistive breathing to task failure in older adults.
Theodorou AA et al. · Nutrients (2023)
Large benefit
← WorseNo effectBetter →
Likely real
The exhaled NO• value was only significantly increased after the supplementation (26% p < 0.001) in the L-citrulline condition.
Pulmonary function, MIP, rate of perceived exertion, and sternocleidomastoid muscle oxygenation were not affected by the L-citrulline supplementation.
In the present study, although short-term L-citrulline supplementation increased exhaled NO•, no ergogenic aids were found on the examined parameters at rest and after resistive breathing to task failure in older adults.
20Strength and enduranceRCTCited 36×n=44 · small study2021
Additional studies are necessary to confirm the effect of citrulline supplementation in sarcopenia delay.
Caballero-García A et al. · Nutrients (2021)
Strength and endurance showed a tendency to increase in the citrulline supplemented group, with no significant differences respect to placebo.
Markers of muscle damage as well as circulating levels of testosterone, cortisol and vitamin D showed no significant changes, but a tendency to improve at the end of intervention in the supplemented group compared to placebo.
Additional studies are necessary to confirm the effect of citrulline supplementation in sarcopenia delay.