Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis.

Systematic review and meta-analysis of double-blind, placebo-controlled crossover trials in healthy adults; eight studies; total 137 participants (101 strength-trained men, 26 strength-trained women, 9 untrained men); mean age 25.4 ± 5.4 years.

Citrulline malate; 6-8 g per acute dose; taken 40-60 minutes before exercise; single-dose prior to resistance training in healthy adults.

Acute CitMal before strength training increased repetitions to failure by 3 ± 5 reps (6.4 ± 7.9%), vs placebo (p = .022; SMD = 0.196). Lower-body subanalysis showed an apparent effect (8.1 ± 8.4%, SMD = 0.27, p = .051); upper-body showed no significant effect (5.7 ± 8.4%, SMD = 0.16, p = .131). Overall, the effect is small. Authors conclude CitMal may delay fatigue and enhance muscle endurance during high-intensity resistance training, suggesting a modest increase in training volume, particularly for lower-body work. The results are heterogeneous and modest; more research is needed to clarify dosing, timing, and populations.

Small overall sample (137 participants) with only 26 females; moderate heterogeneity (I2 ≈ 35%); potential publication bias indicated by Egger's test and trim-and-fill adjustment; variability in CitMal dose (6-8 g) and timing (40-60 min pre-exercise) and occasional co-ingestion of carbohydrates; several studies did not report randomization methods or adverse events; mostly trained populations limit generalizability; cross-over designs may have carryover effects; few studies measured blood/muscle citrulline or arginine; long-term effects unknown.