Effect of L-Citrulline Supplementation on Blood Pressure: a Systematic Review and Meta-Analysis of Clinical Trials

Several interventional studies assessed the impact of dietary supplements on blood pressure. The aim of the present systematic review and meta-analysis was to determine the efficacy of L-citrulline supplementation on blood pressure. Pubmed, Scopus, Google Scholar, and ISI Web of Science were comprehensively searched until May 2018 to assess whether L-citrulline reduces blood pressure. Human clinical trials which reported the effect of L-citrulline supplementation on aortic and brachial blood pressure were included. Characteristics of studies and potential sources of heterogeneity were tabulated. A subgroup analysis was performed to attenuate observed inter-study heterogeneity. A total of five interventions were found for meta-analysis. The impact of L-citrulline on brachial systolic (change 0.28 mmHg; 95% CI − 2.87, 2.31 mmHg) and diastolic (change − 1.56 mmHg; 95% CI − 4.32, 1.20 mmHg) blood pressure was not significant. Also, there was no changes in aortic systolic (change 0.22 mmHg; 95% CI − 4.81, 4.38 mmHg) and diastolic (change 0.26 mmHg; 95% CI − 2.27, 2.80 mmHg) blood pressure after L-citrulline supplementation. Participants’ body weight status was a source of observed heterogeneity. The present systematic review and meta-analysis suggests that L-citrulline supplementation had no beneficial effect on blood pressure.