The effect of L-arginine supplementation on maximal oxygen uptake: A systematic review and meta-analysis.

BACKGROUND The efficacy and safety of L-arginine supplements and their effect on maximal oxygen uptake (VO2 max) remained unclear. This systematic review aimed to investigate the effect of L-arginine supplementation (LAS) on VO2 max in healthy people. METHODS We searched PubMed, Scopus, Web of Science, Cochrane, Embase, ProQuest, and Ovid to identify all relevant literature investigating the effect of LAS on VO2 max. This meta-analysis was conducted via a random-effects model for the best estimation of desired outcomes and studies that meet the inclusion criteria were considered for the final analysis. RESULTS The results of 11 randomized clinical trials indicated that LAS increased VO2 max compared to the control group. There was no significant heterogeneity in this meta-analysis. Subgroup analysis detected that arginine in the form of LAS significantly increased VO2 max compared to the other forms (weighted mean difference = 0.11 L min-1 , I2  = 0.0%, p for heterogeneity = 0.485). CONCLUSIONS This meta-analysis indicated that supplementation with L-arginine could increase VO2 max in healthy people. Further studies are warranted to confirm this finding and to identify the underlying mechanisms.