L-Citrulline
Research reviewed: up until 03/2023
L-Citrulline is a dietary supplement with 8 published peer-reviewed studies involving 124 participants, researched for Performance enhancement, Blood pressure.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Performance enhancement
StrongBlood pressure
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Performance enhancement
Systematic review Intervention under study: L-citrulline supplementation before exercise Studies reviewed: 13 studies comprising 206 participants
Study Type
Systematic review Intervention under study: L-citrulline supplementation before exercise Studies reviewed: 13 studies comprising 206 participants
Results
The results show a correlation between citrulline supplements and significant reductions in the rate of perceived exhaustion during physical activity and muscle soreness 24h and 48h after exercise. The results suggest that athletes may benefit from ingesting either L-citrulline alone or 1h before exercise to resist fatigue.
Randomised controlled trial
Study Type
Randomised controlled trial
Dose
6 g L-citrulline-malate 2 h prior exercise
Participants
17 male pre-professional cyclists
Duration
Acute (before and after a 137-km cycling race)
Results
After the cycling race, growth hormone levels were higher among participants taking L-citrulline malate than among participants in the control group. L-citrulline supplementation was also associated with higher levels of arginine-derived metabolites such as nitrite, creatinine, ornithine and urea.
Randomised placebo-controlled crossover trial
Study Type
Randomised placebo-controlled crossover trial
Dose
2.4g of L-citrulline for 7 days and 2.4 g of L-citrulline 1h before a 4-km cycling time trial on day 8.
Participants
22 athletically-trained males
Duration
8 days
Results
Compared to the placebo, L-citrulline supplementation was associated with a 1.5% reduction in the time taken to complete a 4-km cycling time trial. It was also associated with significant increases in plasma L-arginine levels.
Randomised double-blind placebo-controlled trial
Study Type
Randomised double-blind placebo-controlled trial
Dose
There were 4 dosage groups: 3 g/kg/day of citrulline plus 3 mg/kg/day of nitrates 3 g/kg/day of only citrulline 3 mg/kg/day of only nitrate Placebo
Participants
32 male amateur triathletes with more than 5 years of experience
Duration
9 weeks
Results
The study found that 3 g/day of citrulline and 2.1 g/day of beetroot (300 mg/day of dietary nitrate) for 9 weeks was associated with increased maximal and endurance strength. When compared to citrulline or beetroot supplementation alone, the combination of both supplements was associated with improved performance in tests related to aerobic power.
Blood pressure
Randomised controlled trial
Study Type
Randomised controlled trial
Dose
3g of citrulline tablets per day
Participants
12 young adults with normal blood pressure
Duration
1 week
Results
Citrulline consumption was associated with a 6% reduction in systolic blood pressure and a 14% reduction in diastolic blood pressure.
Randomised controlled trial
Study Type
Randomised controlled trial
Dose
3g per day
Participants
Heart failure patients
Duration
2 months
Results
L-citrulline supplementation was associated with significant reductions in systolic and diastolic arterial blood pressure.
Randomised controlled trial
Study Type
Randomised controlled trial
Participants
41 obese postmenopausal women
Duration
8 weeks
Results
L-citrulline supplementation was associated with significant reductions in blood pressure.
Systematic review Intervention under study: Oral supplementation with L-citrulline Studies reviewed: 8 randomised controlled trials
Study Type
Systematic review Intervention under study: Oral supplementation with L-citrulline Studies reviewed: 8 randomised controlled trials
Results
The results suggest that L-citrulline supplementation may reduce systolic blood pressure (-4 mmHg). A significant reduction in diastolic blood pressure was observed only in the studies that used doses greater than 6 g of L-citrulline per day.
Frequently Asked Questions
Common questions about L-Citrulline research
There are currently 8 peer-reviewed studies on L-Citrulline, involving 124 total participants. Research covers Performance enhancement, Blood pressure. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (7 human studies), and reported outcomes.
L-Citrulline has been researched for: Performance enhancement, Blood pressure. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 7 out of 8 studies are human trials. Human trials carry more weight in our evidence scoring system.
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