The Study
Changes in resistance training performance, rating of perceived exertion, and blood biomarkers after six weeks of supplementation with L-citrulline vs. L-citrulline DL-malate in resistance-trained men: a double-blind placebo-controlled trial
This study gave different supplements to men who lift weights and saw that one group got a little better at doing more reps with their arms. It doesn't prove the supplement caused it, but it's the best kind of test we have—like a fair race where no one knew who got what. So we can say it 'might help' arm endurance, but we can't be sure.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if taking citrulline pills for 6 weeks helps people do more push-ups and bench presses without getting tired as fast.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 559 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — doing 9–10 more reps per workout adds up to significantly more training volume over weeks, which can help build endurance and potentially muscle over time.
- 2People who took citrulline (8g or 12g daily) could do about 9–10 more reps on bench press and incline press compared to those who took a placebo.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of the International Society of Sports Nutrition
Year
2025
Authors
Davoud Bayat, Mohammad Azizi, Naser Behpour, G. Tinsley
Related Content
Claims (6)
Taking citrulline supplements may help improve blood flow and allow more repetitions during high-repetition, short-rest workouts, but it does not cause measurable increases in muscle size over time.
Taking 8 grams of L-citrulline or 12 grams of L-citrulline DL-malate daily for six weeks may help resistance-trained men perform more repetitions to failure in bench press and incline press exercises compared to taking a placebo.
In men who regularly lift weights, taking L-citrulline or citrulline malate supplements for six weeks does not lead to greater increases in maximum strength compared to not taking them, even though everyone in the study got stronger.
In men who regularly lift weights, taking L-citrulline and citrulline malate leads to similar improvements in upper body endurance and nitric oxide metabolite levels after exercise, meaning adding malate does not provide extra performance benefits.
Taking L-citrulline or citrulline malate regularly may raise levels of nitric oxide metabolites after exercise in men who train with weights, and both forms appear to have comparable effects.
Taking L-citrulline or citrulline malate supplements does not lower the levels of lactate or urea in the blood after resistance exercise in men who regularly train with weights.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.