Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of double-blind, placebo-controlled randomized trials.
PubMed 34010809 · doi:10.1123/ijsnem.2020-0295
What was done
A systematic review and meta-analysis of double-blind, placebo-controlled trials examining the acute effect of citrulline malate (CitMal; 6–8 g taken 40–60 min pre-exercise) on repetitions to voluntary muscular failure during upper- and lower-body resistance exercise. Eight studies comprising 137 healthy participants (101 strength-trained men, 26 strength-trained women, and 9 untrained men) met inclusion criteria. Standardized mean differences (SMD, Hedges's g) across 14 single- and multi-joint exercises (~70% of 1RM, averaging 51 ± 23 repetitions across 5 ± 3 sets) were pooled using a random-effects model.
What was found
CitMal supplementation increased total repetitions to failure by 3 ± 5 repetitions (6.4 ± 7.9%) compared to placebo, showing a small statistically significant effect (SMD = 0.196, p = .022). In subanalyses, lower-body exercise showed a trend toward improvement (8.1 ± 8.4%, SMD = 0.27, p = .051), whereas upper-body exercise showed no statistically significant difference (5.7 ± 8.4%, SMD = 0.16, p = .131).
Why it matters
This meta-analysis provides pooled quantitative evidence that acute citrulline malate intake produces a modest ergogenic benefit on muscular endurance during resistance training.
Limits
The total sample size was small (137 participants across 8 studies) and heavily skewed toward trained men, limiting generalizability to women and untrained individuals. The absolute effect size was small, and subanalyses were likely underpowered.
Cited by
- supports Citrulline supplementation at a dose of at least 6 grams improves fatigue resistance during exercise.