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Lci6.0
L-Citrulline Research
Likely helps
188 peer-reviewed studies
What the evidence says
Likely helps
L-Citrulline appears to help in 8 of 10 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1991–2026 with a typical study size of 33 participants.
Based on 188 studies · 21 meta-analyses · 146 RCTs · 888,406 total participants
Confidence
High confidence
What the studies found
8helped2unclear· 178 more without graded effect data
By outcome
Heart & blood pressureReduces blood pressure via sustained nitric oxide production · 4-8 weeks
Likely helps132 studies
Endurance & exercise performanceImproved endurance and reduced fatigue · 1-2 weeks consistent use · Increases NO availability and exercise tolerance · 30-60 minutes
Mostly mechanism / observational50 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 / observational9 studies
Weight management
Mostly mechanism / observational9 studies
Therapeutic & clinical
Mostly mechanism / observational8 studies
Cholesterol & lipidsReduces blood pressure via sustained nitric oxide production · 4-8 weeks
Mostly mechanism / observational5 studies
Safety profile
Mostly mechanism / observational3 studies
Inflammation
Too few graded studies2 studies
Men's vitalityImproved erectile function via nitric oxide · 2-4 weeks
Too few graded studies2 studies
By the numbers
Pulled from 33 studies with measurable effects
Likely real effects
57%
across studies
People studied
888k
typical study: 33 people
Strongest designs
167
21 pooled, 146 randomised
Showed benefit
70%
7/10 studies
How long studies ran
1–4 weeks
4
1–3 months
5
Populations Studied
General population2
Hypertensive postmenopausal women2
Athletes/exercising individuals1
Middle-aged and elderly individuals1
Active research area
93 studies in the last 5 years · Latest meta-analysis: 2026
199120082026
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.
18Post-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.