Effect of L-citrulline intake on blood pressure in cold environments: A systematic review and meta-analysis of randomized controlled trials


Abstract

Background/Objectives: This study employs systematic review and meta-analysis to integrate existing evidence from Randomized Controlled Trials (RCTs), aiming to evaluate the regulatory effect of L-citrulline supplementation on blood pressure (BP) under cold exposure conditions, to provide evidence-based support for cardiovascular health interventions in low-temperature environments.

Methods: A comprehensive search was performed across four major databases (PubMed, Cochrane, Embase, and Web of Science) from their inception to May 28, 2025. Using RevMan 5.4.1 software, a random-effects model was applied to combine effect sizes for the obtained systolic blood pressure (SBP) and diastolic blood pressure (DBP) data, with results reported as weighted mean difference (WMD) and 95% confidence interval (95% CI).

Results: A total of 6 RCTs investigating the effects of L-citrulline intake on BP in cold environments were included, involving 162 participants (intervention group: 87; control group: 75). Results indicate that L-citrulline intake significantly reduced cold-induced SBP (-9.16 mmHg [95% CI: -10.70 to -7.63], P < 0.00001) and DBP (-5.50 mmHg [95% CI: -8.88 to -2.13], P = 0.001). Subgroup analysis revealed significant reductions in brachial SBP (-8.97 mmHg [95% CI: -11.45 to -6.49], P < 0.00001), aortic SBP (-9.20 mmHg [95% CI: -11.38 to -7.03], P < 0.00001), and aortic DBP (-6.51 mmHg [95% CI: -10.50 to -1.80], P = 0.006). However, brachial DBP reduction did not reach statistical significance but showed a trend toward decrease (-4.85 mmHg [95% CI: -10.20 to 0.50], P = 0.08).

Conclusions: Supplementation with L-citrulline effectively alleviates cold-induced BP elevation and significantly reduces both SBP and DBP, indicating its potential clinical value in assisting BP management under cold climate conditions.
Ask to review this manuscript

Notes for potential reviewers

  • Volunteering is not a guarantee that you will be asked to review. There are many reasons: reviewers must be qualified, there should be no conflicts of interest, a minimum of two reviewers have already accepted an invitation, etc.
  • This is NOT OPEN peer review. The review is single-blind, and all recommendations are sent privately to the Academic Editor handling the manuscript. All reviews are published and reviewers can choose to sign their reviews.
  • What happens after volunteering? It may be a few days before you receive an invitation to review with further instructions. You will need to accept the invitation to then become an official referee for the manuscript. If you do not receive an invitation it is for one of many possible reasons as noted above.

  • PeerJ does not judge submissions based on subjective measures such as novelty, impact or degree of advance. Effectively, reviewers are asked to comment on whether or not the submission is scientifically and technically sound and therefore deserves to join the scientific literature. Our Peer Review criteria can be found on the "Editorial Criteria" page - reviewers are specifically asked to comment on 3 broad areas: "Basic Reporting", "Experimental Design" and "Validity of the Findings".
  • Reviewers are expected to comment in a timely, professional, and constructive manner.
  • Until the article is published, reviewers must regard all information relating to the submission as strictly confidential.
  • When submitting a review, reviewers are given the option to "sign" their review (i.e. to associate their name with their comments). Otherwise, all review comments remain anonymous.
  • All reviews of published articles are published. This includes manuscript files, peer review comments, author rebuttals and revised materials.
  • Each time a decision is made by the Academic Editor, each reviewer will receive a copy of the Decision Letter (which will include the comments of all reviewers).

If you have any questions about submitting your review, please email us at [email protected].