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Lci6.0
L-Citrulline Research
Likely helps
163 peer-reviewed studies
What the evidence says
Probably helps
L-Citrulline helped in about half (2/3) of the studies that measured an effect — promising, but not unanimous.
Most evidence is from high-quality meta-analyses and randomised trials published 1991–2026 with a typical study size of 30 participants.
Based on 163 studies · 15 meta-analyses · 126 RCTs · 884,342 total participants
Confidence
High confidence
What the studies found
2helped1unclear· 160 more without graded effect data
By outcome
Heart & blood pressureReduces blood pressure via sustained nitric oxide production · 4-8 weeks
Probably helps111 studies
Endurance & exercise performanceImproved endurance and reduced fatigue · 1-2 weeks consistent use · Increases NO availability and exercise tolerance · 30-60 minutes
RecoveryUp to 40% reduction in muscle soreness · 24-48 hours post-exercise
Too few graded studies15 studies
Lean body mass & muscle growthMay improve high-rep performance · 1-2 weeks
Too few graded studies9 studies
Glucose & metabolic
Too few graded studies8 studies
Therapeutic & clinical
Too few graded studies8 studies
Weight management
Too few graded studies7 studies
Cholesterol & lipidsReduces blood pressure via sustained nitric oxide production · 4-8 weeks
Too few graded studies3 studies
Safety profile
Too few graded studies3 studies
Men's vitalityImproved erectile function via nitric oxide · 2-4 weeks
Too few graded studies2 studies
Inflammation
Too few graded studies1 study
By the numbers
Pulled from 26 studies with measurable effects
Likely real effects
67%
across studies
People studied
884k
typical study: 30 people
Strongest designs
141
15 pooled, 126 randomised
Showed benefit
67%
2/3 studies
How long studies ran
1–4 weeks
3
1–3 months
3
Populations Studied
Athletes/exercising individuals3
Hypertensive postmenopausal women2
Diverse populations1
General population1
Active research area
76 studies in the last 5 years · Latest meta-analysis: 2026
199120082026
1Oxidative stress after exerciseMeta-AnalysisCited 3×2023
In plain English: 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%).
In plain English: 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.
In plain English: Foods rich in polyphenols and nitrate provide trivial benefits for endurance exercise performance, although these effects may be food dependent.
d'Unienville NMA et al. · Journal of the International Society of Sports Nutrition (2021)
Barely noticeable benefit
← WorseNo effectBetter →
Could be chance
No effect on exercise performance following consumption of foods rich in L-citrulline was identified (SMD=-0.03, p=0.24).
Foods rich in polyphenols and nitrate provide trivial benefits for endurance exercise performance, although these effects may be food dependent.
Highly trained endurance athletes do not appear to benefit from consuming nitrate-rich foods but may benefit from polyphenol consumption.
In plain English: 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.
In plain English: The generation of endogenous NO then causes positive biochemical, hemodynamic, and vascular effects, remodeling the physio-pathological conditions of those adults that present risk factors for cardiovascular diseases.
Baião DDS, da Silva DVT, Paschoalin VMF. · Nutrients (2025)
By enhancing circulating L-arginine, L-citrulline indirectly improves the synthesis and bioavailability of nitric oxide, promoting smooth muscle vasodilation.
The beneficial effects of oral L-citrulline ingestion through watermelon require additional evidence, but it has already been demonstrated that it does not undergo hepatic metabolism, instead being transported to the kidneys to participate in de novo L-arginine synthesis.
The generation of endogenous NO then causes positive biochemical, hemodynamic, and vascular effects, remodeling the physio-pathological conditions of those adults that present risk factors for cardiovascular diseases.
In plain English: L-arginine may be promising for pre-eclampsia prevention and treatment, but findings should be interpreted cautiously.
Makama M, McDougall ARA, Cao J, Mills K, Nguyen PY, Hastie R, Ammerdorffer A, Gülmezoglu AM, Vogel JP. · BJOG : an international journal of obstetrics and gynaecology (2025)
In prevention trials, L-arginine was associated with a reduced risk of pre-eclampsia (relative risk [RR] 0.52; 95% confidence interval [CI], 0.35, 0.78; low-certainty evidence, four trials) and severe pre-eclampsia (RR 0.23; 95% CI, 0.09, 0.55; low-certainty evidence, three trials).
In treatment trials, L-arginine may reduce mean systolic blood pressure (MD -5.64 mmHg; 95% CI, -10.66, -0.62; very low-certainty evidence, three trials) and fetal growth restriction (RR 0.46; 95% CI, 0.26, 0.81; low-certainty evidence, two trials).
Only one study (36 women) examined L-citrulline and reported no effect on pre-eclampsia or blood pressure.