Acute effects of l-Citrulline vs. Citrulline malate supplementation on resistance training performance, muscle soreness, and blood biomarkers in resistance-trained men: a double-blind placebo-controlled counter-balanced trial

The current study compared the ergogenic effects of L-Citrulline (LC) and Citrulline Malate (CM) supplementation to examine the synergistic potential of LC and malate, as well as examining the effects of higher doses of LC (8 g) and CM (12 g) than commonly utilized. Twenty-two resistance-trained men completed 3 visits, each separated by a week. At each visit, the subjects were randomly assigned to consume either LC, CM, or Placebo (PL) sixty minutes before performing a resistance training (RT) protocol. The protocol consisted of 5 sets to failure of barbell back squat (BBS) and barbell bench press (BBP) at 70% of 1 repetition maximum (1RM). The study also evaluated blood biomarkers such as Nitrate/Nitrite (NOx), lactate, and urea; subjective measures of perceived exertion; and muscle soreness. Our results showed significant time effects for all variables ( p = 0.002 for urea and p = 0.001 for other variables). However, no treatment or interaction effects were observed for total repetitions to failure (RTF), blood biomarkers, perceived exertion, or muscle soreness ( p > 0.05). The results of this study indicate that the acute ingestion of either LC or CM 60 min before an RT protocol failed to increase muscular endurance, improve subjective measures of perceived exertion and soreness, or positively alter the blood biomarkers. These findings may have implications for individuals considering the use of LC or CM as an ergogenic aid to improve their performance during RT protocols.