Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis.
What this study found
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…
- Study & population
- 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.
- Intervention
- Citrulline malate; 6-8 g per acute dose; taken 40-60 minutes before exercise; single-dose prior to resistance training in healthy adults.
- Key limitation
- 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…
View source
Open PDFOriginal abstract
Citrulline malate (CitMal) is a dietary supplement that is suggested to enhance strength training performance. However, there is conflicting evidence on this matter. Thus, the purpose of this meta-analysis was to determine whether supplementing with CitMal prior to strength training could increase the total number of repetitions performed before reaching voluntary muscular failure. A systematic search was conducted wherein the inclusion criteria were double-blind, placebo-controlled studies in healthy participants that examined the effect of CitMal on repetitions to failure during upper body and lower body resistance exercises. The Hedges's g standardized mean differences (SMD) between the placebo and CitMal trials were calculated and used in a random effect model. Two separate subanalyses were performed for upper body and lower body exercises. Eight studies, including 137 participants who consisted of strength-trained men (n = 101) and women (n = 26) in addition to untrained men (n = 9), fulfilled the inclusion criteria. Across the studies, 14 single-joint and multijoint exercises were performed with an average of 51 ± 23 total repetitions during 5 ± 3 sets per exercise at ∼70% of one-repetition maximum. Supplementing with 6-8 g of CitMal 40-60 min before exercise increased repetitions by 3 ± 5 (6.4 ± 7.9%) compared with placebo (p = .022) with a small SMD (0.196). The subanalysis for the lower body resulted in a tendency for an effect of the supplement (8.1 ± 8.4%, SMD: 0.27, p = .051) with no significant effect for the upper body (5.7 ± 8.4%, SMD: 0.16, p = .131). The current analysis observed a small ergogenic effect of CitMal compared with placebo. Acute CitMal supplementation may, therefore, delay fatigue and enhance muscle endurance during high-intensity strength training.