Acute Effects of Citrulline Supplementation on High-Intensity Strength and Power Performance: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of placebo-controlled trials
PubMed 30895562 · doi:10.1007/s40279-019-01091-z
What was done
The authors conducted a systematic review and meta-analysis across three databases to evaluate the acute effects of citrulline supplementation on high-intensity strength and power performance in healthy men and women. Included studies required a placebo control, a citrulline dose of at least 3 g given at least 30 minutes pre-exercise, and multirepetitive actions of large muscle groups (resistance training sets or sprints ≤30 s). Studies combining citrulline with other ergogenic ingredients (e.g., creatine, caffeine, nitrates) or evaluating small muscle groups/single jumps were excluded.
What was found
Twelve studies with 13 independent samples (total n = 198) met inclusion criteria. Heterogeneity across studies was negligible (Cochrane's Q = 6.9, p = 0.86; I² = 0.0% [95% CI 0.0–40.0%], τ² = 0.0). Citrulline supplementation resulted in a statistically significant improvement compared to placebo (p = 0.036), with a small pooled effect size (standardized mean difference / Hedges' g = 0.20, 95% CI 0.01–0.39). Confidence intervals for every individual included study crossed the line of null effect.
Why it matters
This review quantifies the acute ergogenic potential of isolated citrulline for high-intensity strength and power tasks, demonstrating a small benefit that may be practically relevant for competitive athletes operating on small margins.
Limits
The total pooled sample size was modest (198 participants across 12 studies), and every individual trial was underpowered to detect an effect on its own. The abstract does not report potential moderating effects of citrulline form (e.g., L-citrulline vs. citrulline malate), specific dosing thresholds, training status, or participant sex.
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